React to moving IsAvailable to ISession

Author: JunTaoLuo

src/Microsoft.AspNetCore.Session/DistributedSession.cs

@@ -30,6 +30,7 @@ public class DistributedSession : ISession
         private readonly ILogger _logger;
         private bool _isModified;
         private bool _loaded;
+        private bool _isAvailable;
         private bool _isNewSessionKey;
         private string _sessionId;
         private byte[] _sessionIdBytes;
@@ -71,7 +72,13 @@ public DistributedSession(
             _isNewSessionKey = isNewSessionKey;
         }
 
-        public bool IsAvailable { private set; get; }
+        public bool IsAvailable
+        {
+            get
+            {
+                return _isAvailable;
+            }
+        }
 
         public string Id
         {
@@ -206,12 +213,12 @@ private void Load()
                     {
                         _logger.AccessingExpiredSession(_sessionKey);
                     }
-                    IsAvailable = true;
+                    _isAvailable = true;
                 }
                 catch (Exception exception)
                 {
                     _logger.SessionCacheReadException(_sessionKey, exception);
-                    IsAvailable = false;
+                    _isAvailable = false;
                 }
                 finally
                 {
@@ -235,7 +242,7 @@ public async Task LoadAsync()
                 {
                     _logger.AccessingExpiredSession(_sessionKey);
                 }
-                IsAvailable = true;
+                _isAvailable = true;
                 _loaded = true;
             }
         }