Chapter 8

1. A callback is a function (or more generally, any executable code) that is passed as a parameter to another function in order to be called immediately (synchronous callbacks) or at a later time (asynchronous callbacks). A delegate is a strongly typed callback.
2. A delegate is defined using the delegate keyword. The declaration looks like a function signature, but the compiler actually introduces a class that can hold references to methods whose signatures match the signature of the delegate. Events are variables of a delegate type declared with the event keyword.
3. There are two kinds of tuples in C#: reference tuples, represented by the System.Tuple class, and value tuples, represented by the System.ValueTuple structure. The reference tuples can only hold up to eight elements, while the latter can hold a sequence of any number of elements, although at least two are required. Value tuples may have compile-type named fields, and have a simpler but richer syntax for...