@Override
              public void onCancellationRequested() {
                if (future.cancel(false)) {
                  callback.onCancellation();
                }
              }
Network fetcher that uses the simplest Android stack.

<p>Apps requiring more sophisticated networking should implement their own {@link
NetworkFetcher}.
imagepipeline/src/main/java/com/facebook/imagepipeline/producers/HttpUrlConnectionNetworkFetcher.java