public void clear() {
    if (mIsAttached) {
      for (int i = 0; i < mHolders.size(); ++i) {
        mHolders.get(i).onDetach();
      }
    }
    mHolders.clear();
  }
Releases resources used to display the image.

<p>The containing view must call this method from both {@link View#onStartTemporaryDetach()}
and {@link View#onDetachedFromWindow()}.
drawee/src/main/java/com/facebook/drawee/view/MultiDraweeHolder.java