Ping Cleanup (#2530)

Tidied up some comments, to make the ResetPing client behavior easier to understand.

Will ping in debug mode for consistency. If this becomes a problem when debugging, developers can disable the pings manually. It's easier to fix something noisy, than try to diagnose inconsistently missing behavior.

src/Microsoft.AspNetCore.SignalR.Client.Core/HubConnection.cs

@@ -12,7 +12,6 @@ using System.Threading;
 using System.Threading.Channels;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Connections;
-using Microsoft.AspNetCore.Connections.Features;
 using Microsoft.AspNetCore.Internal;
 using Microsoft.AspNetCore.SignalR.Client.Internal;
 using Microsoft.AspNetCore.SignalR.Protocol;
@@ -556,6 +555,9 @@ namespace Microsoft.AspNetCore.SignalR.Client
 
         private async Task<(bool close, Exception exception)> ProcessMessagesAsync(HubMessage message, ConnectionState connectionState)
         {
+            Log.ResettingKeepAliveTimer(_logger);
+            ResetTimeout();
+
             InvocationRequest irq;
             switch (message)
             {
@@ -601,7 +603,7 @@ namespace Microsoft.AspNetCore.SignalR.Client
                     }
                 case PingMessage _:
                     Log.ReceivedPing(_logger);
-                    // Nothing to do on receipt of a ping.
+                    // timeout is reset above, on receiving any message
                     break;
                 default:
                     throw new InvalidOperationException($"Unexpected message type: {message.GetType().FullName}");
@@ -777,9 +779,6 @@ namespace Microsoft.AspNetCore.SignalR.Client
                         }
                         else if (!buffer.IsEmpty)
                         {
-                            Log.ResettingKeepAliveTimer(_logger);
-                            ResetTimeout();
-
                             Log.ProcessingMessage(_logger, buffer.Length);
 
                             var close = false;

src/Microsoft.AspNetCore.SignalR.Core/HubConnectionContext.cs

@@ -7,7 +7,6 @@ using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO.Pipelines;
-using System.Runtime.ExceptionServices;
 using System.Security.Claims;
 using System.Threading;
 using System.Threading.Tasks;