copy method
Implementation
TaskState copy(
    {bool? refreshing,
    bool? loading,
    bool? refreshNoMore,
    bool? loadNoMore}) {
  return TaskState(
    refreshing: refreshing ?? this.refreshing,
    loading: loading ?? this.loading,
    refreshNoMore: refreshNoMore ?? this.refreshNoMore,
    loadNoMore: loadNoMore ?? this.loadNoMore,
  );
}