docs: @NonNull
      public IconicsDrawable paddingPx(@Dimension(unit = PX) int sizePx) {
          if (mIconPadding != sizePx) {
              mIconPadding = sizePx;
              if (mDrawContour) {
                  mIconPadding += mContourWidth;
              }
              if (mDrawBackgroundContour) {
                  mIconPadding += mBackgroundContourWidth;
              }
  
              invalidateSelf();
          }
          return this;
      }