currentSize property
The number of code units comprising the current rune.
Returns zero if there is no current rune (current is -1).
Implementation
int get currentSize => _nextPosition - _position;© 2012 the Dart project authors
Licensed under the BSD 3-Clause "New" or "Revised" License.
https://api.dart.dev/stable/2.18.5/dart-core/RuneIterator/currentSize.html