свойство length
переопределение
Количество пар ключ/значение в карте.
Реализация
int get length {
return _count;
}
© 2012 the Dart project authors
Licensed under the BSD 3-Clause "New" or "Revised" License.
https://api.dart.dev/stable/2.19.6/dart-collection/SplayTreeMap/length.html
