add method Null safety

GestureArenaEntry add(
  1. int pointer,
  2. GestureArenaMember member
)

Adds a new member (e.g., gesture recognizer) to the arena.

Implementation

GestureArenaEntry add(int pointer, GestureArenaMember member) {
  final _GestureArena state = _arenas.putIfAbsent(pointer, () {
    assert(_debugLogDiagnostic(pointer, '★ Opening new gesture arena.'));
    return _GestureArena();
  });
  state.add(member);
  assert(_debugLogDiagnostic(pointer, 'Adding: $member'));
  return GestureArenaEntry._(this, pointer, member);
}