off method
Implementation
void off(eventName, {String eventReceive = ''}) {
var list = _eMap[eventName];
if (list == null) return;
if (list.isEmpty) {
_eMap.remove(eventName);
return;
}
if (_eMap[eventName]![eventReceive] is List<Function>) {
_eMap[eventName]?.remove(eventReceive);
}
}