make sure there is only **one** path that can cause endpoints to be added, and...

make sure there is only **one** path that can cause endpoints to be added, and ensure that the activation happens after the constructor - removes race condition that can lead to abandoned endpoints; note as part of this, switch the server-snapshot to span-based

StackExchange.Redis/StackExchange/Redis/ExceptionFactory.cs

@@ -104,7 +104,7 @@ internal static string GetInnerMostExceptionMessage(Exception e)
             }
         }
 
-        internal static Exception NoConnectionAvailable(bool includeDetail, bool includePerformanceCounters, RedisCommand command, Message message, ServerEndPoint server, ServerEndPoint[] serverSnapshot)
+        internal static Exception NoConnectionAvailable(bool includeDetail, bool includePerformanceCounters, RedisCommand command, Message message, ServerEndPoint server, ReadOnlySpan<ServerEndPoint> serverSnapshot)
         {
             string commandLabel = GetLabel(includeDetail, command, message);
 
@@ -138,7 +138,7 @@ internal static Exception NoConnectionAvailable(bool includeDetail, bool include
             return ex;
         }
 
-        internal static Exception PopulateInnerExceptions(ServerEndPoint[] serverSnapshot)
+        internal static Exception PopulateInnerExceptions(ReadOnlySpan<ServerEndPoint> serverSnapshot)
         {
             var innerExceptions = new List<Exception>();
             if (serverSnapshot != null)

StackExchange.Redis/StackExchange/Redis/ServerEndPoint.cs

@@ -53,7 +53,6 @@ public ServerEndPoint(ConnectionMultiplexer multiplexer, EndPoint endpoint, Text
             isSlave = false;
             databases = 0;
             writeEverySeconds = config.KeepAlive > 0 ? config.KeepAlive : 60;
-            interactive = CreateBridge(ConnectionType.Interactive, log);
             serverType = ServerType.Standalone;
 
             // overrides for twemproxy
@@ -635,7 +634,6 @@ internal void WriteDirectOrQueueFireAndForget<T>(PhysicalConnection connection,
                 }
             }
         }
-
         private PhysicalBridge CreateBridge(ConnectionType type, TextWriter log)
         {
             Multiplexer.Trace(type.ToString());

StackExchange.Redis/StackExchange/Redis/SocketManager.cs

@@ -163,11 +163,11 @@ internal async void BeginConnectAsync(EndPoint endpoint, Socket socket, Physical
             try
             {
                 if (socket.ConnectAsync(args))
-                {
+                {   // asynchronous operation is pending
                     ConfigureTimeout(args, multiplexer.RawConfig.ConnectTimeout);
                 }
                 else
-                {
+                {   // completed synchronously
                     SocketAwaitable.OnCompleted(args);
                 }
 
@@ -177,7 +177,8 @@ internal async void BeginConnectAsync(EndPoint endpoint, Socket socket, Physical
                     bool ignoreConnect = false;
                     ShouldIgnoreConnect(physicalConnection, ref ignoreConnect);
                     if (ignoreConnect) return;
-                    await awaitable;
+
+                    await awaitable; // wait for the connect to complete or fail (will throw)
 
                     switch (physicalConnection == null ? SocketMode.Abort : await physicalConnection.ConnectedAsync(socket, log, this).ForAwait())
                     {