add method

void add(T newVal)

Adds a new item to the list

Implementation

void add(T newVal) {
  final updatedValue = [...value, newVal];
  final change = GgChange(
    newValue: updatedValue,
    oldValue: value,
    type: GgChangeType.insert,
    index: value.length,
  );
  _syncAndApplyChange(change);
}