/// <summary> /// Initializes a new instance of the <see cref="DataSource"/> class. /// </summary> /// <param name="id">The source of data.</param> /// <exception cref="ArgumentNullException"> /// <paramref name="id"/> is <b>null</b>. /// </exception> protected DataSource(DataSourceId id) { this.Id = id ?? throw new ArgumentNullException("id"); }