static @NotNull ShadowColor shadowColor(final @NotNull ARGBLike argb) {
    if (argb instanceof ShadowColor) {
      return (ShadowColor) argb;
    }

    return shadowColor(argb.red(), argb.green(), argb.blue(), argb.alpha());
  }
Create a shadow color from an existing ARGB colour.

@param argb the existing color
@return a shadow colour
@since 4.18.0
api/src/main/java/net/kyori/adventure/text/format/ShadowColor.java