/// <summary>
/// The <see cref="AggregateException"/> is re-created, with the optional <c>message</c>. Note that the
/// incoming <see cref="AggregateException"/> may be null: if so, a new instance is created. The <c>error</c>
/// argument is inserted into the <see cref="AggregateException.InnerExceptions"/> list at the beginning. If
/// the <c>message</c> is not null, it is set as the <see cref="Exception.Message"/>; and if null, the
/// <c>error</c>'s Message is used.
/// </summary>
/// <param name="aggregateException">Notice: can be null.</param>
/// <param name="error">Not null</param>
/// <param name="message">If null or whitespace, will be set to the <c>error</c>'s Message.</param>
/// <returns>Not null.</returns>
/// <exception cref="ArgumentNullException"></exception>
public static AggregateException AggregateError(
this AggregateException aggregateException,
Exception error,
string message = null)
=> aggregateException.AggregateError(
(newMessage, innerExceptions) => new AggregateException(newMessage, innerExceptions),
error,
message);
