Do not send tracers when running second iteration of cluster nodes di…

…scovery (#2520)

Sending tracers is not necessary because we just connected to the nodes a few seconds ago. It causes problems because sent tracers do not have enough time to respond.

src/StackExchange.Redis/ConnectionMultiplexer.cs

@@ -1478,8 +1478,9 @@ internal async Task<bool> ReconfigureAsync(bool first, bool reconfigureAll, LogP
                             servers[i] = server;
 
                             // This awaits either the endpoint's initial connection, or a tracer if we're already connected
-                            // (which is the reconfigure case)
-                            available[i] = server.OnConnectedAsync(log, sendTracerIfConnected: true, autoConfigureIfConnected: reconfigureAll);
+                            // (which is the reconfigure case, except second iteration which is only for newly discovered cluster members).
+                            var isFirstIteration = iter == 0;
+                            available[i] = server.OnConnectedAsync(log, sendTracerIfConnected: isFirstIteration, autoConfigureIfConnected: reconfigureAll);
                         }
 
                         watch ??= ValueStopwatch.StartNew();