docs: public int findIndexByLayerId(int id) {
          final ChildDrawable[] layers = mLayerState.mChildren;
          final int N = mLayerState.mNum;
          for (int i = 0; i < N; i++) {
              final ChildDrawable childDrawable = layers[i];
              if (childDrawable.mId == id) {
                  return i;
              }
          }
  
          return -1;
      }