code: @Override
    public boolean cancel(final boolean mayInterruptIfRunning) {
      try {
        return cancel(mayInterruptIfRunning, Optional.<Long>empty(), Optional.<TimeUnit>empty());
      } catch (final TimeoutException e) {
        // This should never happen.
        LOG.log(Level.WARNING, "Received a TimeoutException in VortexFuture.cancel(). Should not have occurred.");
        return false;
      }
    }
docs: Sends a cancel signal and blocks and waits until the task is cancelled, completed, or failed.
  @return true if task did not start or was cancelled, false if task failed or completed