@Override
  public void produceResults(Consumer<Void> consumer, ProducerContext producerContext) {
    DelegatingConsumer<T, Void> swallowResultConsumer =
        new DelegatingConsumer<T, Void>(consumer) {
          @Override
          protected void onNewResultImpl(@Nullable T newResult, @Status int status) {
            if (isLast(status)) {
              getConsumer().onNewResult(null, status);
            }
          }
        };
    mInputProducer.produceResults(swallowResultConsumer, producerContext);
  }
Swallow result producer.

<p>This producer just inserts a consumer that swallows results into the stack of consumers.
imagepipeline/src/main/java/com/facebook/imagepipeline/producers/SwallowResultProducer.java