@Override public EventListener create(Call call) {
        long callId = nextCallId.getAndIncrement();
        System.out.printf("%04d %s%n", callId, call.request().url());
        return new PrintingEventListener(callId, System.nanoTime());
      }
    };

    final long callId;
    final long callStartNanos;

    PrintingEventListener(long callId, long callStartNanos) {
      this.callId = callId;

    }

    @Override public void callEnd(Call call) {
      printEvent("callEnd");
    }

    @Override public void callFailed(Call call, IOException ioe) {
      printEvent("callFailed");
    }

    @Override public void canceled(Call call) {
      printEvent("canceled");
    }
  }

    thread.start();
  }

  /**
   * This request body makes it possible for another thread to stream data to the uploading request.
   * This is potentially useful for posting live event streams like video capture. Callers should
   * write to {@code sink()} and close it to complete the post.
   */
  static final class PipeBody extends RequestBody {
    private final Pipe pipe = new Pipe(8192);