initialize static method
void
initialize()
Implementation
static void initialize() {
if (_initialized) return;
_startListener = (html.Event event) {
isComposing = true;
};
_endListener = (html.Event event) {
isComposing = false;
};
html.document.addEventListener('compositionstart', _startListener);
html.document.addEventListener('compositionend', _endListener);
_initialized = true;
}