startTracking method

GroupTracker startTracking(
  1. GroupRef newRef, [
  2. int position = 1
])

Implementation

GroupTracker startTracking(GroupRef newRef, [int position = 1]) {
  var isDuplicate = _positions.containsKey(newRef);
  if (isDuplicate) throw ArgumentError("Ref is invalid because it was used multiple times!", "ref");

  assert (!_positions.containsKey(newRef));
  return GroupTracker._create(
    {
      ..._positions,
      newRef: position,
    },
    _groupCount,
    _previouslyIgnoredRefs,
  );
}