State Machines
In C#, the async and await keywords are used to simplify asynchronous programming. Under the hood, the compiler transforms asynchronous methods into state machines. This transformation allows the method to pause execution at await points and resume later without blocking the main thread. The state machine keeps track of the current state of the method, enabling it to handle asynchronous operations seamlessly.
The C# compiler generates state machines automatically. However, when working with runtime expression trees, the compiler does not provide this functionality. As a result, developers must manually generate state machines.