graphemeAt method
Implementation
String? graphemeAt(int offset) {
if (offset < 0 || offset >= length) {
return null;
}
final position = positionForOffset(offset);
if (position.column == lineLength(position.line) &&
position.line < _storage.lineCount - 1) {
return '\n';
}
return _storage.graphemeInLineAt(position.line, position.column);
}