async and await

The async and await keywords are how C# expresses asynchronous code in a way that still reads top-to-bottom like ordinary synchronous code. The compiler does the heavy lifting: it rewrites the method into a state machine that can pause at any await, return control to the caller, and resume later when the awaited operation finishes. This lesson covers what each keyword does, the return types an async method can use, how exceptions flow back to the caller, and the naming convention that the .NET ecosystem follows.