anchor.diff:  part of testredis;
   
  -Future test_performance(int n){
  +Future test_performance(int n,[bool piping = true]){
     int N = n;
     int rec=0;
     int start;
  
positive.code:   Duration zero = new Duration(seconds:0);
    return conn.connect('localhost',6379).then((Command command){
      start =  new DateTime.now().millisecondsSinceEpoch;
      //command.pipe_start();
      command.send_object(["SET","test","0"]);
      for(int i=1;i<=N;i++){
        command.send_object(["INCR","test"])
  
negative.code:       double perf = N/diff;
        print("  $N operations done in $diff s\n  performance $perf/s");
      });
      if(piping){
        command.pipe_end();
      }
      return r;
    });
  }
  