diff --git a/.github/actions/ci/action.yml b/.github/actions/ci/action.yml
index 4293ff7..94ab372 100644
--- a/.github/actions/ci/action.yml
+++ b/.github/actions/ci/action.yml
@@ -1,8 +1,11 @@
 name: CI Workflow
-description: 'Shared CI workflow.'
+description: "Shared CI workflow."
 inputs:
   ruby-version:
-    description: 'The version of ruby to setup and run'
+    description: "The version of ruby to setup and run"
+    required: true
+  token:
+    description: "GH token used to fetch the SDK test harness"
     required: true
 
 runs:
@@ -11,11 +14,10 @@ runs:
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ inputs.ruby-version }}
-        bundler: 2.2.10
 
     - name: Install dependencies
       shell: bash
-      run: bundle _2.2.10_ install
+      run: bundle install
 
     - name: Skip end to end tests for jruby
       if: ${{ startsWith(inputs.ruby-version, 'jruby') }}
@@ -24,9 +26,28 @@ runs:
 
     - name: Run tests
       shell: bash
-      run: bundle _2.2.10_ exec rspec spec
+      run: bundle exec rspec spec
+
+    - name: Run RuboCop
+      if: ${{ !startsWith(inputs.ruby-version, 'jruby') }}
+      shell: bash
+      run: bundle exec rubocop --parallel
+
+    - name: Build contract tests
+      if: ${{ !startsWith(inputs.ruby-version, 'jruby') }}
+      shell: bash
+      run: make build-contract-tests
 
-    - name: Run contract tests
+    - name: Start contract test service
       if: ${{ !startsWith(inputs.ruby-version, 'jruby') }}
       shell: bash
-      run: make contract-tests
+      run: make start-contract-test-service-bg
+
+    - uses: launchdarkly/gh-actions/actions/contract-tests@contract-tests-v1.1.0
+      if: ${{ !startsWith(inputs.ruby-version, 'jruby') }}
+      with:
+        test_service_port: 8000
+        token: ${{ inputs.token }}
+        repo: sse-contract-tests
+        branch: main
+        version: v1
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0d33d58..80bf00a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,13 +1,13 @@
 name: Run CI
 on:
   push:
-    branches: [ main ]
+    branches: [main]
     paths-ignore:
-      - '**.md' # Do not need to run CI for markdown changes.
+      - "**.md" # Do not need to run CI for markdown changes.
   pull_request:
-    branches: [ main ]
+    branches: [main]
     paths-ignore:
-      - '**.md'
+      - "**.md"
 
 jobs:
   build:
@@ -17,14 +17,11 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version:
-          - '2.5'
-          - '2.6'
-          - '2.7'
-          - '3.0'
-          - '3.1'
-          - '3.2'
-          - jruby-9.3
+          - "3.2"
+          - "3.3"
+          - "3.4"
           - jruby-9.4
+          - jruby-10.0
 
     steps:
       - uses: actions/checkout@v4
@@ -34,3 +31,4 @@ jobs:
       - uses: ./.github/actions/ci
         with:
           ruby-version: ${{ matrix.ruby-version }}
+          token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/manual-publish.yml b/.github/workflows/manual-publish.yml
index 770d4c5..9adcc89 100644
--- a/.github/workflows/manual-publish.yml
+++ b/.github/workflows/manual-publish.yml
@@ -3,7 +3,7 @@ on:
   workflow_dispatch:
     inputs:
       dry_run:
-        description: 'Is this a dry run. If so no package will be published.'
+        description: "Is this a dry run. If so no package will be published."
         type: boolean
         required: true
 
@@ -18,16 +18,17 @@ jobs:
       - uses: actions/checkout@v4
 
       - uses: launchdarkly/gh-actions/actions/release-secrets@release-secrets-v1.2.0
-        name: 'Get rubygems API key'
+        name: "Get rubygems API key"
         with:
           aws_assume_role: ${{ vars.AWS_ROLE_ARN }}
-          ssm_parameter_pairs: '/production/common/releasing/rubygems/api_key = GEM_HOST_API_KEY'
+          ssm_parameter_pairs: "/production/common/releasing/rubygems/api_key = GEM_HOST_API_KEY"
 
       - id: build-and-test
         name: Build and Test
         uses: ./.github/actions/ci
         with:
-          ruby-version: '3.0'
+          ruby-version: "3.2"
+          token: ${{ secrets.GITHUB_TOKEN }}
 
       - id: publish
         name: Publish Package
diff --git a/.github/workflows/release-please.yml b/.github/workflows/release-please.yml
index d55f8fa..8aec81b 100644
--- a/.github/workflows/release-please.yml
+++ b/.github/workflows/release-please.yml
@@ -23,15 +23,16 @@ jobs:
 
       - uses: launchdarkly/gh-actions/actions/release-secrets@release-secrets-v1.2.0
         if: ${{ steps.release.outputs.releases_created == 'true' }}
-        name: 'Get rubygems API key'
+        name: "Get rubygems API key"
         with:
           aws_assume_role: ${{ vars.AWS_ROLE_ARN }}
-          ssm_parameter_pairs: '/production/common/releasing/rubygems/api_key = GEM_HOST_API_KEY'
+          ssm_parameter_pairs: "/production/common/releasing/rubygems/api_key = GEM_HOST_API_KEY"
 
       - uses: ./.github/actions/ci
         if: ${{ steps.release.outputs.releases_created == 'true' }}
         with:
-          ruby-version: '3.0'
+          ruby-version: "3.2"
+          token: ${{ secrets.GITHUB_TOKEN }}
 
       - uses: ./.github/actions/publish
         if: ${{ steps.release.outputs.releases_created == 'true' }}
diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..43d65d5
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,889 @@
+require:
+  - rubocop-performance
+
+AllCops:
+  TargetRubyVersion: 3.1
+  Include:
+    - lib/**/*.rb
+    - spec/**/*.rb
+    - contract-tests/**/*.rb
+  NewCops: disable
+
+Naming/AccessorMethodName:
+  Description: Check the naming of accessor methods for get_/set_.
+  Enabled: false
+
+Style/AccessModifierDeclarations:
+  Description: "Access modifiers should be declared to apply to a group of methods or inline before each method, depending on configuration."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#alias-method"
+  Enabled: false
+
+Style/Alias:
+  Description: "Use alias_method instead of alias."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#alias-method"
+  Enabled: false
+
+Style/ArrayJoin:
+  Description: "Use Array#join instead of Array#*."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#array-join"
+  Enabled: false
+
+Style/AsciiComments:
+  Description: "Use only ascii symbols in comments."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#english-comments"
+  Enabled: false
+
+Naming/AsciiIdentifiers:
+  Description: "Use only ascii symbols in identifiers."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#english-identifiers"
+  Enabled: false
+
+Naming/VariableName:
+  Description: "Makes sure that all variables use the configured style, snake_case or camelCase, for their names."
+  Enabled: false
+
+Style/Attr:
+  Description: "Checks for uses of Module#attr."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#attr"
+  Enabled: false
+
+Metrics/AbcSize:
+  Description: "Checks that the ABC size of methods is not higher than the configured maximum."
+  Enabled: false
+
+Metrics/BlockLength:
+  Description: "Checks if the length of a block exceeds some maximum value."
+  Enabled: false
+
+Metrics/BlockNesting:
+  Description: "Avoid excessive block nesting"
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#three-is-the-number-thou-shalt-count"
+  Enabled: false
+
+Style/CaseEquality:
+  Description: "Avoid explicit use of the case equality operator(===)."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-case-equality"
+  Enabled: false
+
+Style/CharacterLiteral:
+  Description: "Checks for uses of character literals."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-character-literals"
+  Enabled: false
+
+Style/ClassAndModuleChildren:
+  Description: "Checks style of children classes and modules."
+  Enabled: true
+  EnforcedStyle: nested
+
+Metrics/ClassLength:
+  Description: "Avoid classes longer than 100 lines of code."
+  Enabled: false
+
+Metrics/ModuleLength:
+  Description: "Avoid modules longer than 100 lines of code."
+  Enabled: false
+
+Style/ClassVars:
+  Description: "Avoid the use of class variables."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-class-vars"
+  Enabled: false
+
+Style/CollectionMethods:
+  Enabled: true
+  PreferredMethods:
+    find: detect
+    inject: reduce
+    collect: map
+    find_all: select
+
+Style/ColonMethodCall:
+  Description: "Do not use :: for method call."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#double-colons"
+  Enabled: false
+
+Style/CommentAnnotation:
+  Description: >-
+    Checks formatting of special comments
+    (TODO, FIXME, OPTIMIZE, HACK, REVIEW).
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#annotate-keywords"
+  Enabled: false
+
+Metrics/CyclomaticComplexity:
+  Description: >-
+    A complexity metric that is strongly correlated to the number
+    of test cases needed to validate a method.
+  Enabled: false
+
+Style/PreferredHashMethods:
+  Description: "Checks for use of deprecated Hash methods."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#hash-key"
+  Enabled: false
+
+Style/Documentation:
+  Description: "Document classes and non-namespace modules."
+  Enabled: false
+
+Style/DoubleNegation:
+  Description: "Checks for uses of double negation (!!)."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-bang-bang"
+  Enabled: false
+
+Style/EachWithObject:
+  Description: "Prefer `each_with_object` over `inject` or `reduce`."
+  Enabled: false
+
+Style/EmptyLiteral:
+  Description: "Prefer literals to Array.new/Hash.new/String.new."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#literal-array-hash"
+  Enabled: false
+
+# Checks whether the source file has a utf-8 encoding comment or not
+# AutoCorrectEncodingComment must match the regex
+# /#.*coding\s?[:=]\s?(?:UTF|utf)-8/
+Style/Encoding:
+  Enabled: false
+
+Style/EvenOdd:
+  Description: "Favor the use of Fixnum#even? && Fixnum#odd?"
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#predicate-methods"
+  Enabled: false
+
+Naming/FileName:
+  Description: "Use snake_case for source file names."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#snake-case-files"
+  Enabled: false
+
+Lint/FlipFlop:
+  Description: "Checks for flip flops"
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-flip-flops"
+  Enabled: false
+
+Style/FrozenStringLiteralComment:
+  Description: "Helps you transition from mutable string literals to frozen string literals."
+  Enabled: false
+
+Style/FormatString:
+  Description: "Enforce the use of Kernel#sprintf, Kernel#format or String#%."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#sprintf"
+  Enabled: false
+
+Style/GlobalVars:
+  Description: "Do not introduce global variables."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#instance-vars"
+  Reference: "https://www.zenspider.com/ruby/quickref.html"
+  Enabled: false
+
+Style/GuardClause:
+  Description: "Check for conditionals that can be replaced with guard clauses"
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-nested-conditionals"
+  Enabled: false
+
+Style/IfUnlessModifier:
+  Description: >-
+    Favor modifier if/unless usage when you have a
+    single-line body.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#if-as-a-modifier"
+  Enabled: false
+
+Style/IfWithSemicolon:
+  Description: "Do not use if x; .... Use the ternary operator instead."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-semicolon-ifs"
+  Enabled: false
+
+Style/InlineComment:
+  Description: "Avoid inline comments."
+  Enabled: false
+
+Style/Lambda:
+  Description: "Use the new lambda literal syntax for single-line blocks."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#lambda-multi-line"
+  Enabled: false
+
+Style/LambdaCall:
+  Description: "Use lambda.call(...) instead of lambda.(...)."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#proc-call"
+  Enabled: false
+
+Style/LineEndConcatenation:
+  Description: >-
+    Use \ instead of + or << to concatenate two string literals at
+    line end.
+  Enabled: false
+
+Layout/LineLength:
+  Description: "Limit lines to 150 characters."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#80-character-limits"
+  Max: 180
+
+Metrics/MethodLength:
+  Description: "Avoid methods longer than 10 lines of code."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#short-methods"
+  Enabled: false
+
+Style/ModuleFunction:
+  Description: "Checks for usage of `extend self` in modules."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#module-function"
+  Enabled: false
+
+Style/NegatedIf:
+  Description: >-
+    Favor unless over if for negative conditions
+    (or control flow or).
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#unless-for-negatives"
+  Enabled: true
+
+Style/NegatedWhile:
+  Description: "Favor until over while for negative conditions."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#until-for-negatives"
+  Enabled: true
+
+Style/Next:
+  Description: "Use `next` to skip iteration instead of a condition at the end."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-nested-conditionals"
+  Enabled: false
+
+Style/NilComparison:
+  Description: "Prefer x.nil? to x == nil."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#predicate-methods"
+  Enabled: false
+
+Style/Not:
+  Description: "Use ! instead of not."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#bang-not-not"
+  Enabled: false
+
+Style/NumericLiterals:
+  Description: >-
+    Add underscores to large numeric literals to improve their
+    readability.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#underscores-in-numerics"
+  Enabled: false
+
+Style/OneLineConditional:
+  Description: >-
+    Favor the ternary operator(?:) over
+    if/then/else/end constructs.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#ternary-operator"
+  Enabled: false
+
+Naming/BinaryOperatorParameterName:
+  Description: "When defining binary operators, name the argument other."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#other-arg"
+  Enabled: false
+
+Metrics/ParameterLists:
+  Description: "Avoid parameter lists longer than three or four parameters."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#too-many-params"
+  Enabled: false
+
+Metrics/PerceivedComplexity:
+  Enabled: false
+
+Style/PercentLiteralDelimiters:
+  Description: "Use `%`-literal delimiters consistently"
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#percent-literal-braces"
+  Enabled: false
+
+Style/PerlBackrefs:
+  Description: "Avoid Perl-style regex back references."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-perl-regexp-last-matchers"
+  Enabled: false
+
+Naming/PredicateName:
+  Description: "Check the names of predicate methods."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#bool-methods-qmark"
+  ForbiddenPrefixes:
+    - is_
+  Exclude:
+    - spec/**/*
+
+Style/Proc:
+  Description: "Use proc instead of Proc.new."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#proc"
+  Enabled: false
+
+Style/RaiseArgs:
+  Description: "Checks the arguments passed to raise/fail."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#exception-class-messages"
+  Enabled: false
+
+Style/RegexpLiteral:
+  Description: "Use / or %r around regular expressions."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#percent-r"
+  Enabled: false
+
+Style/SelfAssignment:
+  Description: >-
+    Checks for places where self-assignment shorthand should have
+    been used.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#self-assignment"
+  Enabled: false
+
+Style/SingleLineBlockParams:
+  Description: "Enforces the names of some block params."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#reduce-blocks"
+  Enabled: false
+
+Style/SingleLineMethods:
+  Description: "Avoid single-line methods."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-single-line-methods"
+  Enabled: false
+
+Style/SignalException:
+  Description: "Checks for proper usage of fail and raise."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#fail-method"
+  Enabled: false
+
+Style/SpecialGlobalVars:
+  Description: "Avoid Perl-style global variables."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-cryptic-perlisms"
+  Enabled: false
+
+Style/StringLiterals:
+  Description: "Checks if uses of quotes match the configured preference."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#consistent-string-literals"
+  EnforcedStyle: double_quotes
+  Enabled: false
+
+Style/TrailingCommaInArguments:
+  Description: "Checks for trailing comma in argument lists."
+  StyleGuide: "#no-trailing-params-comma"
+  Enabled: true
+
+Style/TrailingCommaInArrayLiteral:
+  Description: "Checks for trailing comma in array and hash literals."
+  EnforcedStyleForMultiline: comma
+
+Style/TrailingCommaInHashLiteral:
+  Description: "Checks for trailing comma in array and hash literals."
+  EnforcedStyleForMultiline: comma
+
+Style/TrivialAccessors:
+  Description: "Prefer attr_* methods to trivial readers/writers."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#attr_family"
+  Enabled: false
+
+Style/VariableInterpolation:
+  Description: >-
+    Don't interpolate global, instance and class variables
+    directly in strings.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#curlies-interpolate"
+  Enabled: false
+
+Style/WhenThen:
+  Description: "Use when x then ... for one-line cases."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#one-line-cases"
+  Enabled: false
+
+Style/WhileUntilModifier:
+  Description: >-
+    Favor modifier while/until usage when you have a
+    single-line body.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#while-as-a-modifier"
+  Enabled: false
+
+Style/WordArray:
+  Description: "Use %w or %W for arrays of words."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#percent-w"
+  Enabled: false
+
+# Layout
+Layout/DotPosition:
+  Description: "Checks the position of the dot in multi-line method calls."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#consistent-multi-line-chains"
+  EnforcedStyle: leading
+
+Layout/ExtraSpacing:
+  Description: "Do not use unnecessary spacing."
+  Enabled: true
+  AllowBeforeTrailingComments: true
+
+Layout/MultilineOperationIndentation:
+  Description: >-
+    Checks indentation of binary operations that span more than
+    one line.
+  Enabled: true
+  EnforcedStyle: indented
+
+Layout/InitialIndentation:
+  Description: >-
+    Checks the indentation of the first non-blank non-comment line in a file.
+  Enabled: false
+
+Layout/SpaceInsideArrayLiteralBrackets:
+  Description: "Checks that brackets used for array literals have or don't have surrounding space depending on configuration."
+  Enabled: false
+
+Layout/TrailingWhitespace:
+  Description: "Ensures all trailing whitespace has been removed"
+  Enabled: true
+
+# Lint
+
+Lint/AmbiguousOperator:
+  Description: >-
+    Checks for ambiguous operators in the first argument of a
+    method invocation without parentheses.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#parens-as-args"
+  Enabled: false
+
+Lint/AmbiguousRegexpLiteral:
+  Description: >-
+    Checks for ambiguous regexp literals in the first argument of
+    a method invocation without parenthesis.
+  Enabled: false
+
+Lint/AssignmentInCondition:
+  Description: "Don't use assignment in conditions."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#safe-assignment-in-condition"
+  Enabled: false
+
+Lint/CircularArgumentReference:
+  Description: "Don't refer to the keyword argument in the default value."
+  Enabled: false
+
+Layout/ConditionPosition:
+  Description: >-
+    Checks for condition placed in a confusing position relative to
+    the keyword.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#same-line-condition"
+  Enabled: false
+
+Lint/DeprecatedClassMethods:
+  Description: "Check for deprecated class method calls."
+  Enabled: false
+
+Lint/DuplicateHashKey:
+  Description: "Check for duplicate keys in hash literals."
+  Enabled: false
+
+Lint/EachWithObjectArgument:
+  Description: "Check for immutable argument given to each_with_object."
+  Enabled: false
+
+Lint/ElseLayout:
+  Description: "Check for odd code arrangement in an else block."
+  Enabled: false
+
+Lint/FormatParameterMismatch:
+  Description: "The number of parameters to format/sprint must match the fields."
+  Enabled: false
+
+Lint/SuppressedException:
+  Description: "Don't suppress exception."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#dont-hide-exceptions"
+  Enabled: false
+
+Lint/LiteralAsCondition:
+  Description: "Checks of literals used in conditions."
+  Enabled: false
+
+Lint/LiteralInInterpolation:
+  Description: "Checks for literals used in interpolation."
+  Enabled: false
+
+Lint/Loop:
+  Description: >-
+    Use Kernel#loop with break rather than begin/end/until or
+    begin/end/while for post-loop tests.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#loop-with-break"
+  Enabled: false
+
+Lint/NestedMethodDefinition:
+  Description: "Do not use nested method definitions."
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#no-nested-methods"
+  Enabled: false
+
+Lint/NonLocalExitFromIterator:
+  Description: "Do not use return in iterator to cause non-local exit."
+  Enabled: false
+
+Lint/ParenthesesAsGroupedExpression:
+  Description: >-
+    Checks for method calls with a space before the opening
+    parenthesis.
+  StyleGuide: "https://github.com/bbatsov/ruby-style-guide#parens-no-spaces"
+  Enabled: false
+
+Lint/RequireParentheses:
+  Description: >-
+    Use parentheses in the method call to avoid confusion
+    about precedence.
+  Enabled: false
+
+Lint/UnderscorePrefixedVariableName:
+  Description: "Do not use prefix `_` for a variable that is used."
+  Enabled: false
+
+Lint/RedundantCopDisableDirective:
+  Description: >-
+    Checks for rubocop:disable comments that can be removed.
+    Note: this cop is not disabled when disabling all cops.
+    It must be explicitly disabled.
+  Enabled: false
+
+Lint/Void:
+  Description: "Possible use of operator/literal/variable in void context."
+  Enabled: false
+
+# Performance
+
+Performance/CaseWhenSplat:
+  Description: >-
+    Place `when` conditions that use splat at the end
+    of the list of `when` branches.
+  Enabled: false
+
+Performance/Count:
+  Description: >-
+    Use `count` instead of `select...size`, `reject...size`,
+    `select...count`, `reject...count`, `select...length`,
+    and `reject...length`.
+  Enabled: false
+
+Performance/Detect:
+  Description: >-
+    Use `detect` instead of `select.first`, `find_all.first`,
+    `select.last`, and `find_all.last`.
+  Reference: "https://github.com/JuanitoFatas/fast-ruby#enumerabledetect-vs-enumerableselectfirst-code"
+  Enabled: false
+
+Performance/FlatMap:
+  Description: >-
+    Use `Enumerable#flat_map`
+    instead of `Enumerable#map...Array#flatten(1)`
+    or `Enumberable#collect..Array#flatten(1)`
+  Reference: "https://github.com/JuanitoFatas/fast-ruby#enumerablemaparrayflatten-vs-enumerableflat_map-code"
+  Enabled: false
+
+Performance/ReverseEach:
+  Description: "Use `reverse_each` instead of `reverse.each`."
+  Reference: "https://github.com/JuanitoFatas/fast-ruby#enumerablereverseeach-vs-enumerablereverse_each-code"
+  Enabled: false
+
+Style/Sample:
+  Description: >-
+    Use `sample` instead of `shuffle.first`,
+    `shuffle.last`, and `shuffle[Fixnum]`.
+  Reference: "https://github.com/JuanitoFatas/fast-ruby#arrayshufflefirst-vs-arraysample-code"
+  Enabled: false
+
+Performance/Size:
+  Description: >-
+    Use `size` instead of `count` for counting
+    the number of elements in `Array` and `Hash`.
+  Reference: "https://github.com/JuanitoFatas/fast-ruby#arraycount-vs-arraysize-code"
+  Enabled: false
+
+Performance/StringReplacement:
+  Description: >-
+    Use `tr` instead of `gsub` when you are replacing the same
+    number of characters. Use `delete` instead of `gsub` when
+    you are deleting characters.
+  Reference: "https://github.com/JuanitoFatas/fast-ruby#stringgsub-vs-stringtr-code"
+  Enabled: false
+
+# Disabled temporarily while we bring code base inline
+Layout/ArgumentAlignment:
+  Enabled: false
+
+Layout/ArrayAlignment:
+  Enabled: false
+
+Layout/BlockEndNewline:
+  Enabled: false
+
+Layout/CaseIndentation:
+  Enabled: false
+
+Layout/ClosingHeredocIndentation:
+  Enabled: false
+
+Layout/ClosingParenthesisIndentation:
+  Enabled: false
+
+Layout/CommentIndentation:
+  Enabled: false
+
+Layout/ElseAlignment:
+  Enabled: false
+
+Layout/EmptyLineAfterGuardClause:
+  Enabled: false
+
+Layout/EmptyLineBetweenDefs:
+  Enabled: false
+
+Layout/EmptyLines:
+  Enabled: false
+
+Layout/EmptyLinesAroundBlockBody:
+  Enabled: false
+
+Layout/EmptyLinesAroundMethodBody:
+  Enabled: false
+
+Layout/EmptyLinesAroundModuleBody:
+  Enabled: false
+
+Layout/EndAlignment:
+  Enabled: false
+
+Layout/FirstArgumentIndentation:
+  Enabled: false
+
+Layout/FirstHashElementIndentation:
+  Enabled: false
+
+Layout/HashAlignment:
+  Enabled: false
+
+Layout/HeredocIndentation:
+  Enabled: false
+
+Layout/IndentationWidth:
+  Enabled: false
+
+Layout/LeadingCommentSpace:
+  Enabled: false
+
+Layout/LeadingEmptyLines:
+  Enabled: false
+
+Layout/MultilineArrayBraceLayout:
+  Enabled: false
+
+Layout/MultilineBlockLayout:
+  Enabled: false
+
+Layout/MultilineHashBraceLayout:
+  Enabled: false
+
+Layout/MultilineMethodCallBraceLayout:
+  Enabled: false
+
+Layout/MultilineMethodCallIndentation:
+  Enabled: false
+
+Layout/ParameterAlignment:
+  Enabled: false
+
+Layout/SpaceAfterComma:
+  Enabled: false
+
+Layout/SpaceAroundBlockParameters:
+  Enabled: false
+
+Layout/SpaceAroundEqualsInParameterDefault:
+  Enabled: false
+
+Layout/SpaceAroundOperators:
+  Enabled: false
+
+Layout/SpaceBeforeBlockBraces:
+  Enabled: false
+
+Layout/SpaceBeforeComma:
+  Enabled: false
+
+Layout/SpaceInsideBlockBraces:
+  Enabled: false
+
+Layout/SpaceInsideHashLiteralBraces:
+  Enabled: false
+
+Layout/SpaceInsideReferenceBrackets:
+  Enabled: false
+
+Layout/TrailingEmptyLines:
+  Enabled: false
+
+Lint/ConstantDefinitionInBlock:
+  Enabled: false
+
+Lint/IneffectiveAccessModifier:
+  Enabled: false
+
+Lint/MissingCopEnableDirective:
+  Enabled: false
+
+Lint/RedundantRequireStatement:
+  Enabled: false
+
+Lint/StructNewOverride:
+  Enabled: false
+
+Lint/UnusedBlockArgument:
+  Enabled: false
+
+Lint/UnusedMethodArgument:
+  Enabled: false
+
+Lint/UselessAccessModifier:
+  Enabled: false
+
+Lint/UselessAssignment:
+  Enabled: false
+
+Lint/UselessMethodDefinition:
+  Enabled: false
+
+Naming/BlockParameterName:
+  Enabled: false
+
+Naming/HeredocDelimiterNaming:
+  Enabled: false
+
+Naming/MethodParameterName:
+  Enabled: false
+
+Naming/RescuedExceptionsVariableName:
+  Enabled: false
+
+Naming/VariableNumber:
+  Enabled: false
+
+Style/AccessorGrouping:
+  Enabled: false
+
+Style/AndOr:
+  Enabled: false
+
+Style/BlockDelimiters:
+  Enabled: false
+
+Style/CaseLikeIf:
+  Enabled: false
+
+Style/CombinableLoops:
+  Enabled: false
+
+Style/CommentedKeyword:
+  Enabled: false
+
+Style/ConditionalAssignment:
+  Enabled: false
+
+Style/DefWithParentheses:
+  Enabled: false
+
+Style/EmptyElse:
+  Enabled: false
+
+Style/EmptyMethod:
+  Enabled: false
+
+Style/ExplicitBlockArgument:
+  Enabled: false
+
+Style/For:
+  Enabled: false
+
+Style/FormatStringToken:
+  Enabled: false
+
+Style/GlobalStdStream:
+  Enabled: false
+
+Style/HashEachMethods:
+  Enabled: false
+
+Style/HashSyntax:
+  Enabled: false
+
+Style/InfiniteLoop:
+  Enabled: false
+
+Style/InverseMethods:
+  Enabled: false
+
+Style/MethodCallWithoutArgsParentheses:
+  Enabled: false
+
+Style/MissingRespondToMissing:
+  Enabled: false
+
+Style/MultilineIfThen:
+  Enabled: false
+
+Style/MultilineTernaryOperator:
+  Enabled: false
+
+Style/MultipleComparison:
+  Enabled: false
+
+Style/MutableConstant:
+  Enabled: false
+
+Style/NumericPredicate:
+  Enabled: false
+
+Style/OptionalBooleanParameter:
+  Enabled: false
+
+Style/ParallelAssignment:
+  Enabled: false
+
+Style/RedundantAssignment:
+  Enabled: false
+
+Style/RedundantBegin:
+  Enabled: false
+
+Style/RedundantCondition:
+  Enabled: true
+
+Style/RedundantException:
+  Enabled: false
+
+Style/RedundantFileExtensionInRequire:
+  Enabled: false
+
+Style/RedundantParentheses:
+  Enabled: true
+
+Style/RedundantRegexpEscape:
+  Enabled: false
+
+Style/RedundantReturn:
+  Enabled: true
+
+Style/RedundantSelf:
+  Enabled: false
+
+Style/RescueStandardError:
+  Enabled: false
+
+Style/SafeNavigation:
+  Enabled: false
+
+Style/Semicolon:
+  Enabled: true
+  AllowAsExpressionSeparator: true
+
+Style/SlicingWithRange:
+  Enabled: false
+
+Style/SoleNestedConditional:
+  Enabled: false
+
+Style/StringConcatenation:
+  Enabled: false
+
+Style/SymbolArray:
+  Enabled: false
+
+Style/SymbolProc:
+  Enabled: false
+
+Style/TernaryParentheses:
+  Enabled: false
+
+Style/TrailingUnderscoreVariable:
+  Enabled: false
+
+Style/WhileUntilDo:
+  Enabled: false
+
+Style/ZeroLengthPredicate:
+  Enabled: false
diff --git a/Makefile b/Makefile
index 34a27c6..27c23d0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,10 @@
 TEMP_TEST_OUTPUT=/tmp/sse-contract-test-service.log
 
 build-contract-tests:
-	@cd contract-tests && bundle _2.2.10_ install
+	@cd contract-tests && bundle install
 
 start-contract-test-service:
-	@cd contract-tests && bundle _2.2.10_ exec ruby service.rb
+	@cd contract-tests && bundle exec ruby service.rb
 
 start-contract-test-service-bg:
 	@echo "Test service output will be captured in $(TEMP_TEST_OUTPUT)"
diff --git a/README.md b/README.md
index 2b6e13c..f360d15 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ Parts of this code are based on https://github.com/Tonkpils/celluloid-eventsourc
 Supported Ruby versions
 -----------------------
 
-This gem has a minimum Ruby version of 2.5, or 9.2 for JRuby.
+This gem has a minimum Ruby version of 3.1.
 
 Quick setup
 -----------
diff --git a/contract-tests/Gemfile b/contract-tests/Gemfile
index 84bdd56..7e4c662 100644
--- a/contract-tests/Gemfile
+++ b/contract-tests/Gemfile
@@ -2,9 +2,7 @@ source 'https://rubygems.org'
 
 gem 'ld-eventsource', path: '..'
 
-gem 'sinatra', '~> 2.1'
-# Sinatra can work with several server frameworks. In JRuby, we have to use glassfish (which
-# is only available in JRuby). Otherwise we use thin (which is not available in JRuby).
-gem 'glassfish', :platforms => :jruby
-gem 'thin', :platforms => :ruby
 gem 'json'
+gem 'puma', '~> 6.6'
+gem 'rackup', '~> 2.2'
+gem 'sinatra', '>= 4.1'
diff --git a/contract-tests/service.rb b/contract-tests/service.rb
index 839822c..0a1d303 100644
--- a/contract-tests/service.rb
+++ b/contract-tests/service.rb
@@ -22,8 +22,8 @@
     capabilities: [
       'headers',
       'last-event-id',
-      'read-timeout'
-    ]
+      'read-timeout',
+    ],
   }.to_json
 end
 
@@ -58,8 +58,8 @@
     last_event_id: opts[:lastEventId],
     read_timeout: opts[:readTimeoutMs].nil? ? nil : (opts[:readTimeoutMs].to_f / 1000),
     reconnect_time: opts[:initialDelayMs].nil? ? nil : (opts[:initialDelayMs].to_f / 1000)
-  ) do |sse|
-    entity = StreamEntity.new(sse, tag, callbackUrl)
+  ) do |client|
+    entity = StreamEntity.new(client, tag, callbackUrl)
   end
 
   streams[streamId] = entity
diff --git a/contract-tests/stream_entity.rb b/contract-tests/stream_entity.rb
index 0c62543..078f95a 100644
--- a/contract-tests/stream_entity.rb
+++ b/contract-tests/stream_entity.rb
@@ -23,8 +23,8 @@ def on_event(event)
       event: {
         type: event.type,
         data: event.data,
-        id: event.last_event_id
-      }
+        id: event.last_event_id,
+      },
     }
     self.send_message(message)
   end
@@ -33,7 +33,7 @@ def on_error(error)
     $log.info("#{@tag} Received error from stream: #{error}")
     message = {
       kind: 'error',
-      error: error
+      error: error,
     }
     self.send_message(message)
   end
diff --git a/ld-eventsource.gemspec b/ld-eventsource.gemspec
index d671bc4..de59b25 100644
--- a/ld-eventsource.gemspec
+++ b/ld-eventsource.gemspec
@@ -1,29 +1,31 @@
 # coding: utf-8
 
-lib = File.expand_path("../lib", __FILE__)
+lib = File.expand_path('lib', __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
-require "ld-eventsource/version"
+require 'ld-eventsource/version'
 
-# rubocop:disable Metrics/BlockLength
 Gem::Specification.new do |spec|
-  spec.name          = "ld-eventsource"
+  spec.name          = 'ld-eventsource'
   spec.version       = SSE::VERSION
-  spec.authors       = ["LaunchDarkly"]
-  spec.email         = ["team@launchdarkly.com"]
-  spec.summary       = "LaunchDarkly SSE client"
-  spec.description   = "LaunchDarkly SSE client for Ruby"
-  spec.homepage      = "https://github.com/launchdarkly/ruby-eventsource"
-  spec.license       = "Apache-2.0"
+  spec.authors       = ['LaunchDarkly']
+  spec.email         = ['team@launchdarkly.com']
+  spec.summary       = 'LaunchDarkly SSE client'
+  spec.description   = 'LaunchDarkly SSE client for Ruby'
+  spec.homepage      = 'https://github.com/launchdarkly/ruby-eventsource'
+  spec.license       = 'Apache-2.0'
 
-  spec.files         = Dir.glob("lib/**/*") + ["README.md", "LICENSE"]
+
+  spec.files         = Dir.glob('lib/**/*') + ['README.md', 'LICENSE']
   spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
-  spec.require_paths = ["lib"]
+  spec.require_paths = ['lib']
+  spec.required_ruby_version = '>= 3.1'
 
-  spec.add_development_dependency "bundler", "2.2.10"
-  spec.add_development_dependency "rspec", "~> 3.2"
-  spec.add_development_dependency "rspec_junit_formatter", "~> 0.3.0"
-  spec.add_development_dependency "webrick", "~> 1.7"
+  spec.add_development_dependency 'rspec', '~> 3.2'
+  spec.add_development_dependency 'rspec_junit_formatter', '~> 0.3.0'
+  spec.add_development_dependency "rubocop", "~> 1.37"
+  spec.add_development_dependency "rubocop-performance", "~> 1.15"
+  spec.add_development_dependency 'webrick', '~> 1.7'
 
-  spec.add_runtime_dependency "concurrent-ruby", "~> 1.0"
-  spec.add_runtime_dependency "http", ">= 4.4.1", "< 6.0.0"
+  spec.add_runtime_dependency 'concurrent-ruby', '~> 1.0'
+  spec.add_runtime_dependency 'http', '>= 4.4.1', '< 6.0.0'
 end
diff --git a/lib/ld-eventsource/client.rb b/lib/ld-eventsource/client.rb
index 6355a62..c018151 100644
--- a/lib/ld-eventsource/client.rb
+++ b/lib/ld-eventsource/client.rb
@@ -120,14 +120,14 @@ def initialize(uri,
       if @proxy
         http_client_options["proxy"] = {
           :proxy_address => @proxy.host,
-          :proxy_port => @proxy.port
+          :proxy_port => @proxy.port,
         }
       end
 
       @http_client = HTTP::Client.new(http_client_options)
         .timeout({
           read: read_timeout,
-          connect: connect_timeout
+          connect: connect_timeout,
         })
       @cxn = nil
       @lock = Mutex.new
@@ -202,13 +202,13 @@ def closed?
     private
 
     def reset_http
-      @http_client.close if !@http_client.nil?
+      @http_client.close unless @http_client.nil?
       close_connection
     end
 
     def close_connection
       @lock.synchronize do
-        @cxn.connection.close if !@cxn.nil?
+        @cxn.connection.close unless @cxn.nil?
         @cxn = nil
       end
     end
@@ -216,12 +216,12 @@ def close_connection
     def default_logger
       log = ::Logger.new($stdout)
       log.level = ::Logger::WARN
-      log.progname  = 'ld-eventsource'
+      log.progname = 'ld-eventsource'
       log
     end
 
     def run_stream
-      while !@stopped.value
+      until @stopped.value
         close_connection
         begin
           resp = connect
@@ -231,7 +231,7 @@ def run_stream
           # There's a potential race if close was called in the middle of the previous line, i.e. after we
           # connected but before @cxn was set. Checking the variable again is a bit clunky but avoids that.
           return if @stopped.value
-          read_stream(resp) if !resp.nil?
+          read_stream(resp) unless resp.nil?
         rescue => e
           # When we deliberately close the connection, it will usually trigger an exception. The exact type
           # of exception depends on the specific Ruby runtime. But @stopped will always be set in this case.
@@ -263,7 +263,7 @@ def connect
         begin
           @logger.info { "Connecting to event stream at #{@uri}" }
           cxn = @http_client.request("GET", @uri, {
-            headers: build_headers
+            headers: build_headers,
           })
           if cxn.status.code == 200
             content_type = cxn.content_type.mime_type
@@ -332,7 +332,7 @@ def read_stream(cxn)
 
     def dispatch_event(event)
       @logger.debug { "Received event: #{event}" }
-      @last_id = event.id if !event.id.nil?
+      @last_id = event.id unless event.id.nil?
 
       # Pass the event to the caller
       @on[:event].call(event)
@@ -353,7 +353,7 @@ def build_headers
       h = {
         'Accept' => 'text/event-stream',
         'Cache-Control' => 'no-cache',
-        'User-Agent' => 'ruby-eventsource'
+        'User-Agent' => 'ruby-eventsource',
       }
       h['Last-Event-Id'] = @last_id if !@last_id.nil? && @last_id != ""
       h.merge(@headers)
diff --git a/lib/ld-eventsource/errors.rb b/lib/ld-eventsource/errors.rb
index 6625642..6fe05ba 100644
--- a/lib/ld-eventsource/errors.rb
+++ b/lib/ld-eventsource/errors.rb
@@ -30,7 +30,7 @@ def initialize(status, message)
     #
     class HTTPContentTypeError < StandardError
       def initialize(type)
-        @content_type =  type
+        @content_type = type
         super("invalid content type \"#{type}\"")
       end
 
diff --git a/lib/ld-eventsource/impl/backoff.rb b/lib/ld-eventsource/impl/backoff.rb
index 543da63..a540bf3 100644
--- a/lib/ld-eventsource/impl/backoff.rb
+++ b/lib/ld-eventsource/impl/backoff.rb
@@ -34,12 +34,12 @@ def initialize(base_interval, max_interval, reconnect_reset_interval: 60)
       # @return [Float]  the next interval in seconds
       #
       def next_interval
-        if !@last_good_time.nil?
+        unless @last_good_time.nil?
           good_duration = Time.now.to_f - @last_good_time
           @attempts = 0 if good_duration >= @reconnect_reset_interval
         end
         @last_good_time = nil
-        target = ([@base_interval * (2 ** @attempts), @max_interval].min).to_f
+        target = [@base_interval * (2 ** @attempts), @max_interval].min.to_f
         @attempts += 1
         if target == 0
           0  # in some Ruby versions it's illegal to call rand(0)
diff --git a/lib/ld-eventsource/impl/event_parser.rb b/lib/ld-eventsource/impl/event_parser.rb
index bb6c8e4..b766aeb 100644
--- a/lib/ld-eventsource/impl/event_parser.rb
+++ b/lib/ld-eventsource/impl/event_parser.rb
@@ -36,7 +36,7 @@ def items
             if line.empty?
               event = maybe_create_event
               reset_buffers
-              gen.yield event if !event.nil?
+              gen.yield event unless event.nil?
             elsif (pos = line.index(':'))
               name = line.slice(0...pos)
 
@@ -45,7 +45,7 @@ def items
               line = line.slice(pos..-1)
 
               item = process_field(name, line)
-              gen.yield item if !item.nil?
+              gen.yield item unless item.nil?
             end
           end
         end
@@ -72,7 +72,7 @@ def process_field(name, value)
             end
             @have_data = true
           when "id"
-            if !value.include?("\x00")
+            unless value.include?("\x00")
               @id = value
               @last_event_id = value
             end
@@ -85,7 +85,7 @@ def process_field(name, value)
       end
 
       def maybe_create_event
-        return nil if !@have_data
+        return nil unless @have_data
         StreamEvent.new(@type || :message, @data, @id, @last_event_id)
       end
     end
diff --git a/spec/backoff_spec.rb b/spec/backoff_spec.rb
index 6a1f9af..e3b81da 100644
--- a/spec/backoff_spec.rb
+++ b/spec/backoff_spec.rb
@@ -52,7 +52,7 @@ module Impl
         initial = 0
         max = 60
         b = Backoff.new(initial, max)
-        
+
         for i in 1..6 do
           interval = b.next_interval
           expect(interval).to eq(0)
diff --git a/spec/buffered_line_reader_spec.rb b/spec/buffered_line_reader_spec.rb
index 376a1fa..a57c7eb 100644
--- a/spec/buffered_line_reader_spec.rb
+++ b/spec/buffered_line_reader_spec.rb
@@ -4,7 +4,7 @@ def make_tests(name, input_line_chunks:, expected_lines:)
   [{
     name: "#{name}: one chunk per line",
     chunks: input_line_chunks,
-    expected: expected_lines
+    expected: expected_lines,
   }].concat(
     (1..4).map do |size|
       # Here we're lumping together all the content into one string and then
@@ -13,11 +13,11 @@ def make_tests(name, input_line_chunks:, expected_lines:)
       # chunks would be ["ab", "cd", "\ne", "fg", "\n"]. This helps to find edge
       # case problems related to line terminators falling at the start of a chunk
       # or in the middle, etc.
-      ({
+      {
         name: "#{name}: #{size}-character chunks",
         chunks: input_line_chunks.join().chars.each_slice(size).map { |a| a.join },
-        expected: expected_lines
-      })
+        expected: expected_lines,
+      }
     end
   )
 end
@@ -43,7 +43,7 @@ def tests_for_terminator(term, desc)
     make_tests("multi-line chunks",
       input_line_chunks: ["first line" + term + "second line" + term + "third",
        " line" + term + "fourth line" + term],
-      expected_lines: ["first line", "second line", "third line", "fourth line"])
+      expected_lines: ["first line", "second line", "third line", "fourth line"]),
   ].flatten
 end
 
@@ -53,7 +53,7 @@ def tests_for_terminator(term, desc)
   terminators = {
     "CR": "\r",
     "LF": "\n",
-    "CRLF": "\r\n"
+    "CRLF": "\r\n",
   }
 
   terminators.each do |desc, term|
diff --git a/spec/client_spec.rb b/spec/client_spec.rb
index 51f516d..ea7b849 100644
--- a/spec/client_spec.rb
+++ b/spec/client_spec.rb
@@ -6,7 +6,7 @@
 #
 describe SSE::Client do
   before(:each) do
-    skip("end-to-end HTTP tests are disabled because they're unreliable on this platform") if !stub_http_server_available?
+    skip("end-to-end HTTP tests are disabled because they're unreliable on this platform") unless stub_http_server_available?
   end
 
   subject { SSE::Client }
@@ -57,7 +57,7 @@ def send_stream_content(res, content, keep_open:)
         requests << req
         send_stream_content(res, "", keep_open: true)
       end
-      
+
       headers = { "Authorization" => "secret" }
 
       with_client(subject.new(server.base_uri, headers: headers)) do |client|
@@ -68,7 +68,7 @@ def send_stream_content(res, content, keep_open:)
           "host" => ["127.0.0.1:" + server.port.to_s],
           "authorization" => ["secret"],
           "user-agent" => ["ruby-eventsource"],
-          "connection" => ["close"]
+          "connection" => ["close"],
         })
       end
     end
@@ -82,7 +82,7 @@ def send_stream_content(res, content, keep_open:)
         requests << req
         send_stream_content(res, "", keep_open: true)
       end
-      
+
       headers = { "Authorization" => "secret" }
 
       with_client(subject.new(server.base_uri, headers: headers, last_event_id: id)) do |client|
@@ -94,7 +94,7 @@ def send_stream_content(res, content, keep_open:)
           "authorization" => ["secret"],
           "last-event-id" => [id],
           "user-agent" => ["ruby-eventsource"],
-          "connection" => ["close"]
+          "connection" => ["close"],
         })
       end
     end
@@ -112,7 +112,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         expect(event_sink.pop).to eq(simple_event_1)
         expect(event_sink.pop).to eq(simple_event_2)
       end
@@ -133,9 +133,9 @@ def send_stream_content(res, content, keep_open:)
         c.on_error { |error| error_sink << error }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         event_sink.pop  # wait till we have definitely started reading the stream
-        client.close
+        c.close
         sleep 0.25  # there's no way to really know when the stream thread has finished
         expect(error_sink.empty?).to be true
       end
@@ -164,7 +164,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_error { |error| error_sink << error }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         expect(event_sink.pop).to eq(simple_event_1)
         expect(error_sink.pop).to eq(SSE::Errors::HTTPStatusError.new(500, "sorry"))
         expect(attempt).to eq 2
@@ -195,7 +195,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_error { |error| error_sink << error }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         expect(event_sink.pop).to eq(simple_event_1)
         expect(error_sink.pop).to eq(SSE::Errors::HTTPContentTypeError.new("text/plain"))
         expect(attempt).to eq 2
@@ -220,7 +220,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         expect(event_sink.pop).to eq(simple_event_1)
         expect(attempt).to eq 2
       end
@@ -241,7 +241,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         expect(event_sink.pop).to eq(simple_event_1)
         expect(event_sink.pop).to eq(simple_event_2)
         expect(attempt).to eq 2
@@ -268,7 +268,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         req1 = requests.pop
         req2 = requests.pop
         expect(req2.header["last-event-id"]).to eq([ "a" ])
@@ -294,7 +294,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         last_interval = nil
         max_requests.times do |i|
           expect(event_sink.pop).to eq(simple_event_1)
@@ -334,7 +334,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         last_interval = nil
         max_requests.times do |i|
           expect(event_sink.pop).to eq(simple_event_1)
@@ -369,7 +369,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         expect(event_sink.pop).to eq(simple_event_1)
         interval = request_times[1] - request_times[0]
         expect(interval).to be < 0.5
@@ -389,7 +389,7 @@ def send_stream_content(res, content, keep_open:)
           c.on_event { |event| event_sink << event }
         end
 
-        with_client(client) do |client|
+        with_client(client) do |c|
           expect(event_sink.pop).to eq(simple_event_1)
           expect(proxy.request_count).to eq(1)
         end
@@ -424,7 +424,7 @@ def send_stream_content(res, content, keep_open:)
         c.on_event { |event| event_sink << event }
       end
 
-      with_client(client) do |client|
+      with_client(client) do |c|
         4.times {
           expect(event_sink.pop).to eq(simple_event_1)
         }
@@ -438,7 +438,7 @@ def send_stream_content(res, content, keep_open:)
       server.setup_response("/") do |req,res|
         send_stream_content(res, "", keep_open: true)
       end
-      
+
       with_client(subject.new(server.base_uri)) do |client|
         expect(client.closed?).to be(false)
 
diff --git a/spec/event_parser_spec.rb b/spec/event_parser_spec.rb
index 264d73d..c77609e 100644
--- a/spec/event_parser_spec.rb
+++ b/spec/event_parser_spec.rb
@@ -12,10 +12,10 @@ def verify_parsed_events(lines:, expected_events:)
   it "parses an event with only data" do
     lines = [
       "data: def",
-      ""
+      "",
     ]
     ep = subject.new(lines)
-    
+
     expected_event = SSE::StreamEvent.new(:message, "def", nil)
     output = ep.items.to_a
     expect(output).to eq([ expected_event ])
@@ -26,10 +26,10 @@ def verify_parsed_events(lines:, expected_events:)
       "event: abc",
       "data: def",
       "id: 1",
-      ""
+      "",
     ]
     ep = subject.new(lines)
-    
+
     expected_event = SSE::StreamEvent.new(:abc, "def", "1", "1")
     output = ep.items.to_a
     expect(output).to eq([ expected_event ])
@@ -39,10 +39,10 @@ def verify_parsed_events(lines:, expected_events:)
     lines = [
       "event: abc",
       "data: def",
-      ""
+      "",
     ]
     ep = subject.new(lines, "1")
-    
+
     expected_event = SSE::StreamEvent.new(:abc, "def", nil, "1")
     output = ep.items.to_a
     expect(output).to eq([ expected_event ])
@@ -53,10 +53,10 @@ def verify_parsed_events(lines:, expected_events:)
       "event: abc",
       "data: def",
       "id:",
-      ""
+      "",
     ]
     ep = subject.new(lines, "1")
-    
+
     expected_event = SSE::StreamEvent.new(:abc, "def", "", "")
     output = ep.items.to_a
     expect(output).to eq([ expected_event ])
@@ -68,23 +68,23 @@ def verify_parsed_events(lines:, expected_events:)
       "event: abc",
       "data: def",
       "id: 12\x0034",
-      ""
+      "",
     ]
     ep = subject.new(lines, "1")
-    
+
     expected_event = SSE::StreamEvent.new(:abc, "def", nil, "1")
     output = ep.items.to_a
     expect(output).to eq([ expected_event ])
   end
-  
+
   it "parses an event with multi-line data" do
     lines = [
       "data: def",
       "data: ghi",
-      ""
+      "",
     ]
     ep = subject.new(lines)
-    
+
     expected_event = SSE::StreamEvent.new(:message, "def\nghi", nil)
     output = ep.items.to_a
     expect(output).to eq([ expected_event ])
@@ -94,10 +94,10 @@ def verify_parsed_events(lines:, expected_events:)
     verify_parsed_events(
       lines: [
         "data:",
-        ""
+        "",
       ],
       expected_events: [
-        SSE::StreamEvent.new(:message, "", nil)
+        SSE::StreamEvent.new(:message, "", nil),
       ])
   end
 
@@ -106,10 +106,10 @@ def verify_parsed_events(lines:, expected_events:)
       lines: [
         "data:",
         "data: abc",
-        ""
+        "",
       ],
       expected_events: [
-        SSE::StreamEvent.new(:message, "\nabc", nil)
+        SSE::StreamEvent.new(:message, "\nabc", nil),
       ])
   end
 
@@ -119,10 +119,10 @@ def verify_parsed_events(lines:, expected_events:)
         "data:",
         "data:",
         "data: abc",
-        ""
+        "",
       ],
       expected_events: [
-        SSE::StreamEvent.new(:message, "\n\nabc", nil)
+        SSE::StreamEvent.new(:message, "\n\nabc", nil),
       ])
   end
 
@@ -132,10 +132,10 @@ def verify_parsed_events(lines:, expected_events:)
         "data: abc",
         "data:",
         "data: def",
-        ""
+        "",
       ],
       expected_events: [
-        SSE::StreamEvent.new(:message, "abc\n\ndef", nil)
+        SSE::StreamEvent.new(:message, "abc\n\ndef", nil),
       ])
   end
 
@@ -144,10 +144,10 @@ def verify_parsed_events(lines:, expected_events:)
       lines: [
         "data: abc",
         "data:",
-        ""
+        "",
       ],
       expected_events: [
-        SSE::StreamEvent.new(:message, "abc\n", nil)
+        SSE::StreamEvent.new(:message, "abc\n", nil),
       ])
   end
 
@@ -156,10 +156,10 @@ def verify_parsed_events(lines:, expected_events:)
       ":",
       "data: def",
       ":",
-      ""
+      "",
     ]
     ep = subject.new(lines)
-    
+
     expected_event = SSE::StreamEvent.new(:message, "def", nil)
     output = ep.items.to_a
     expect(output).to eq([ expected_event ])
@@ -168,7 +168,7 @@ def verify_parsed_events(lines:, expected_events:)
   it "parses reconnect interval" do
     lines = [
       "retry: 2500",
-      ""
+      "",
     ]
     ep = subject.new(lines)
 
@@ -184,10 +184,10 @@ def verify_parsed_events(lines:, expected_events:)
       "id: 1",
       "",
       "data: ghi",
-      ""
+      "",
     ]
     ep = subject.new(lines)
-    
+
     expected_event_1 = SSE::StreamEvent.new(:abc, "def", "1", "1")
     expected_event_2 = SSE::StreamEvent.new(:message, "ghi", nil, "1")
     output = ep.items.to_a
@@ -199,10 +199,10 @@ def verify_parsed_events(lines:, expected_events:)
       "event: nothing",
       "",
       "event: nada",
-      ""
+      "",
     ]
     ep = subject.new(lines)
-    
+
     output = ep.items.to_a
     expect(output).to eq([])
   end
diff --git a/spec/http_stub.rb b/spec/http_stub.rb
index 1fe8da2..3724529 100644
--- a/spec/http_stub.rb
+++ b/spec/http_stub.rb
@@ -62,7 +62,7 @@ def create_server(port)
       AccessLog: [],
       Logger: NullLogger.new,
       ProxyContentHandler: proc do |req,res|
-        if !@connect_status.nil?
+        unless @connect_status.nil?
           res.status = @connect_status
         end
         @request_count += 1