Add underscore prefix to start0

Author: dnadoba

Sources/AsyncHTTPClient/ConnectionPool/HTTP2/HTTP2Connection.swift

@@ -129,7 +129,7 @@ final class HTTP2Connection {
             delegate: delegate,
             logger: logger
         )
-        return connection.start0().map { maxStreams in (connection, maxStreams) }
+        return connection._start0().map { maxStreams in (connection, maxStreams) }
     }
 
     func executeRequest(_ request: HTTPExecutableRequest) {
@@ -164,7 +164,7 @@ final class HTTP2Connection {
         return promise.futureResult
     }
 
-    func start0() -> EventLoopFuture<Int> {
+    func _start0() -> EventLoopFuture<Int> {
         self.channel.eventLoop.assertInEventLoop()
 
         let readyToAcceptConnectionsPromise = self.channel.eventLoop.makePromise(of: Int.self)

Tests/AsyncHTTPClientTests/HTTP2ConnectionTests.swift

@@ -54,7 +54,7 @@ class HTTP2ConnectionTests: XCTestCase {
             delegate: TestHTTP2ConnectionDelegate(),
             logger: logger
         )
-        let startFuture = connection.start0()
+        let startFuture = connection._start0()
 
         XCTAssertNoThrow(try embedded.close().wait())
         // to really destroy the channel we need to tick once