@Nullable
  @Override
  protected Bitmap getValue(Bucket<Bitmap> bucket) {
    Bitmap result = super.getValue(bucket);
    if (result != null) {
      result.eraseColor(Color.TRANSPARENT);
    }
    return result;
  }
Determine if this bitmap is reusable (i.e.) if subsequent {@link #get(int)} requests can use
this value. The bitmap is reusable if - it has not already been recycled AND - it is mutable

@param value the value to test for reusability
@return true, if the bitmap can be reused
imagepipeline/src/main/java/com/facebook/imagepipeline/memory/BucketsBitmapPool.java