Method onDataChange

packages/firebase-database/index.android.ts:212–214

(param0: com.google.firebase.database.DataSnapshot)

			handle = this.native.addValueEventListener(
				new com.google.firebase.database.ValueEventListener({
					onDataChange(param0: com.google.firebase.database.DataSnapshot) {
						callback?.(DataSnapshot.fromNative(param0), null);
					},
					onCancelled(param0: com.google.firebase.database.DatabaseError) {
						const err = FirebaseError.fromNative(param0);
						cancelCallbackOrContext?.(err);