code: @Override
  	protected Future<ActivityData> submit(ActivityCallable callable) {
  		logger.trace("submitting activity to thread pool...");
  		return service.submit(callable);
  	}
docs: Assigns the given activity to the thread pool for background execution.
  
  @param callable
  the callable object for the {@code Activity} to be executed asynchronously.
  @return
  the activity's {@code Future} object, for result retrieval.
  @see
  org.dihedron.patterns.activities.concurrent.ActivityExecutor#submit(org.dihedron.patterns.activities.Activity)