Tests: tweak reconfig

Previously was allowing 0ms to actually get a broadcast

StackExchange.Redis.Tests/Config.cs

@@ -3,6 +3,7 @@
 using System.IO;
 using System.Linq;
 using System.Threading;
+using System.Threading.Tasks;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -14,7 +15,7 @@ public class Config : TestBase
         public Config(ITestOutputHelper output) : base (output) { }
 
         [Fact]
-        public void VerifyReceiveConfigChangeBroadcast()
+        public async Task VerifyReceiveConfigChangeBroadcast()
         {
             var config = GetConfiguration();
             using (var sender = Create(allowAdmin: true))
@@ -26,11 +27,11 @@ public void VerifyReceiveConfigChangeBroadcast()
                     Output.WriteLine("Config changed: " + (a.EndPoint == null ? "(none)" : a.EndPoint.ToString()));
                     Interlocked.Increment(ref total);
                 };
-                Thread.Sleep(500);
                 // send a reconfigure/reconnect message
                 long count = sender.PublishReconfigure();
                 GetServer(receiver).Ping();
                 GetServer(receiver).Ping();
+                await Task.Delay(10).ConfigureAwait(false);
                 Assert.True(count == -1 || count >= 2, "subscribers");
                 Assert.True(Interlocked.CompareExchange(ref total, 0, 0) >= 1, "total (1st)");
 
@@ -40,7 +41,7 @@ public void VerifyReceiveConfigChangeBroadcast()
                 var server = GetServer(sender);
                 if (server.IsSlave) Skip.Inconclusive("didn't expect a slave");
                 server.MakeMaster(ReplicationChangeOptions.Broadcast);
-                Thread.Sleep(100);
+                await Task.Delay(100).ConfigureAwait(false);
                 GetServer(receiver).Ping();
                 GetServer(receiver).Ping();
                 Assert.True(Interlocked.CompareExchange(ref total, 0, 0) >= 1, "total (2nd)");