/// <summary> /// Gets an Actor by the email value held in the repository /// </summary> /// <param name="email">The full email address to look up</param> /// <param name="cancellationToken"></param> /// <returns>The Actor that matched the email address</returns> /// <exception cref="ArgumentNullException"></exception> public async Task <Actor> GetUserByEmailAsync(string email, CancellationToken cancellationToken = default(CancellationToken)) { Actor actor; if (!string.IsNullOrEmpty(email)) { actor = await repository.GetActorByEmailAsync(email, cancellationToken); } else { throw new ArgumentNullException(nameof(email), "Email must be specified"); } return(actor); }