replaceRange method Null safety

CharacterRange replaceRange(
  1. Characters replacement

Replaces the current range with replacement and returns the result.

Replaces the current range in source with replacement and returns a range of the resulting characters which contains the replacement characters.

The inserted characters may combine with the preceding or following code points, so that the start and end of the original range are no longer grapheme cluster boundaries. In that case, the returned range may extend into into the code points before and after the original range.


CharacterRange replaceRange(Characters replacement);