KeepAlive shouldn't bother if the conneciton is already busy

StackExchange.Redis/PhysicalBridge.cs

@@ -235,6 +235,8 @@ internal void IncrementOpCount()
 
         internal void KeepAlive()
         {
+            if (!(physical?.IsIdle() ?? false)) return; // don't pile on if already doing something
+
             var commandMap = Multiplexer.CommandMap;
             Message msg = null;
             var features = ServerEndPoint.GetFeatures();

StackExchange.Redis/PhysicalConnection.cs

@@ -415,6 +415,8 @@ void add(string lk, string sk, string v)
             Shutdown();
         }
 
+
+        internal bool IsIdle() => _writeStatus == WriteStatus.Idle;
         internal void SetIdle() => _writeStatus = WriteStatus.Idle;
         internal void SetWriting() => _writeStatus = WriteStatus.Writing;
 
@@ -428,6 +430,8 @@ private enum WriteStatus
             Flushed,
         }
 
+        /// <summary>Returns a string that represents the current object.</summary>
+        /// <returns>A string that represents the current object.</returns>
         public override string ToString() => $"{physicalName} ({_writeStatus})";
 
         internal static void IdentifyFailureType(Exception exception, ref ConnectionFailureType failureType)