Метод writeCharCode
void writeCharCode(Добавляет строковое представление charCode в буфер.
Исходный код
external void writeCharCode(int charCode);
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/1.24.3/dart-core/StringBuffer/writeCharCode.html