handle method
Implementation
bool handle(dynamic event, FluentDocument document) {
if (event is! KeyEvent) return false;
this.document = document;
updateModifiers(event);
if (document.registry.dispatchKeyEvent(event, document)) return true;
if (handleBackspaceKey(event)) return true;
if (handleDeleteKey(event)) return true;
if (handleMetaActions(event)) return true;
if (handleEnterKey(event)) return true;
if (handleTabKey(event)) return true;
if (handleArrowKeys(event)) return true;
if (handleHomeKey(event)) return true;
if (handleEndKey(event)) return true;
if (handlePageUpKey(event)) return true;
if (handlePageDownKey(event)) return true;
return handleCharacterInput(event);
}