registerItem method

void registerItem(
  1. Object tag,
  2. Future<void> trigger([
    1. Rect (
      1. Rect
      )?
    ])
)

Implementation

void registerItem(Object tag, Future<void> Function([Rect Function(Rect)?]) trigger) {
  assert(
    !items.containsKey(tag),
    'Duplicate OriginItem tag "$tag". Each tag must be unique.',
  );
  items[tag] = trigger;
}