private void initMarginRect(Rect marginRect, MarginLayoutParams marginLayoutParams) {
      marginRect.set(
        marginLayoutParams.leftMargin,
        marginLayoutParams.topMargin,
        marginLayoutParams.rightMargin,
        marginLayoutParams.bottomMargin
    );
  }
Converts {@link MarginLayoutParams} into a representative {@link Rect}.

@param marginRect Rect to be initialized with margins coordinates, where
{@link MarginLayoutParams#leftMargin} is equivalent to {@link Rect#left}, etc.
@param marginLayoutParams margins to populate the Rect with
library/src/main/java/com/timehop/stickyheadersrecyclerview/calculation/DimensionCalculator.java