public static void Validate(AsyncCluster cluster, AsyncQueryValidate.Listener listener, AsyncNode node, string ns, ulong expectedKey)
        {
            string    command = "cluster-stable:namespace=" + ns;
            AsyncInfo aic     = new AsyncInfo(cluster, null, new Handler(listener, command, expectedKey), node, command);

            aic.Execute();
        }
 internal Handler(AsyncQueryValidate.Listener listener, string command, ulong expectedKey)
 {
     this.listener    = listener;
     this.command     = command;
     this.expectedKey = expectedKey;
 }