* with the wall clock time.
     *
     * @return the current instant using monotonic timing
     */
    @Override
    public Instant instant() {
        long elapsedNanos = System.nanoTime() - startNanos;
        return startInstant.plusNanos(elapsedNanos);
    }

    /**
     * Returns the wall clock time captured when this monotonic clock was initialized.
     * <p>

    private void printEvent(String name) {
      long nowNanos = System.nanoTime();
      if (name.equals("callStart")) {
        callStartNanos = nowNanos;
      }
      long elapsedNanos = nowNanos - callStartNanos;
      System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
    }

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

  private void printEvent(String name) {
    long nowNanos = System.nanoTime();
    if (name.equals("callStart")) {
      callStartNanos = nowNanos;
    }
    long elapsedNanos = nowNanos - callStartNanos;
    System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
  }

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

  @Override public void callEnd(Call call) {

      this.callId = callId;
      this.callStartNanos = callStartNanos;
    }

    private void printEvent(String name) {
      long elapsedNanos = System.nanoTime() - callStartNanos;
      System.out.printf("%04d %.3f %s%n", callId, elapsedNanos / 1000000000d, name);
    }

    @Override public void proxySelectStart(Call call, HttpUrl url) {
      printEvent("proxySelectStart");
    }