@Override
  public synchronized void onProgressUpdate(float progress) {
    if (mIsFinished) {
      return;
    }
    try {
      onProgressUpdateImpl(progress);
    } catch (Exception e) {
      onUnhandledException(e);
    }
  }
Called when the progress updates.

@param progress in range [0, 1]
imagepipeline/src/main/java/com/facebook/imagepipeline/producers/BaseConsumer.java