@CancelResult
  public int cancel(@NonNull String tag) {
    if (!driver.isAvailable()) {
      return CANCEL_RESULT_NO_DRIVER_AVAILABLE;
    }

    return driver.cancel(tag);
  }
Attempts to cancel the Job that matches the provided tag and endpoint.

<p>Returns one of the CANCEL_RESULT_ constants.
jobdispatcher/src/main/java/com/firebase/jobdispatcher/FirebaseJobDispatcher.java