code: public ImageVectorizationResult getImageVectorizationResultWait() throws Exception {
  		try {
  			ImageVectorizationResult imvr = pool.take().get();
  			return imvr;
  		} catch (Exception e) {
  			throw e;
  		} finally {
  			// in any case (Exception or not) the numPendingTask should be reduced
  			numPendingTasks--;
  		}
  	}
docs: Gets an image vectorization result from the pool, waiting if necessary.
  
  @return the vectorization result
  @throws Exception
  for a failed vectorization task