unregisterContentObserver method
unregisterContentObserver(observer: ContentObserver): Unit https://developer.android.com/reference/kotlin/android/content/ContentResolver#unregistercontentobserver
Implementation
Future<void> unregisterContentObserver(ContentObserver observer) {
return methodChannel.invokeMethod<void>('unregisterContentObserver', {
'observer': observer.id,
});
}