remove the Sleep from PreserveOrder test

StackExchange.Redis.Tests/Config.cs

@@ -146,7 +146,7 @@ public async Task TestManaulHeartbeat()
 
                 var after = muxer.OperationCount;
 
-                Assert.True(after >= before + 4);
+                Assert.True(after >= before + 4, $"after: {after}, before: {before}");
             }
         }
 
@@ -355,7 +355,7 @@ public async Task TestAutomaticHeartbeat()
                         await Task.Delay(8000).ForAwait();
 
                         var after = innerMuxer.OperationCount;
-                        Assert.True(after >= before + 4);
+                        Assert.True(after >= before + 4, $"after: {after}, before: {before}");
                     }
                 }
                 finally

StackExchange.Redis.Tests/PreserveOrder.cs

@@ -20,7 +20,7 @@ public void Execute()
                 var channel = Me();
                 var received = new List<int>();
                 Log("Subscribing...");
-                const int COUNT = 100;
+                const int COUNT = 500;
                 sub.Subscribe(channel, (_, message) =>
                 {
                     lock (received)
@@ -29,8 +29,6 @@ public void Execute()
                         if (received.Count == COUNT)
                             Monitor.PulseAll(received); // wake the test rig
                     }
-                    Thread.Sleep(1); // you kinda need to be slow, otherwise
-                    // the pool will end up doing everything on one thread
                 });
                 Log("");
                 Log("Sending (any order)...");