Async Return Types

Async methods have three possible return types: Task<TResult>, Task,
and void.

• The Task<TResult> return type is used for an async method that contains a return (C#)
  statement in which the operand has type TResult.
  • The Result property is a blocking property. If
    you try to access it before its task is finished, the thread that's currently active is blocked until the task completes and the value is available. In most cases, you should access the value by using await instead
    of accessing the property directly.

• Async methods that don't contain a return statement or that contain a return statement that doesn't return an operand usually have a return type of Task. Such
  methods would be void-returning methods if they were written to run synchronously. If you use a Task return type for an async method, a calling method can use an await operator
  to suspend the caller's completion until the called async method has finished.

• The primary use of the void return type is in event handlers, where a void return type is required. A
  void return also can be used to override void-returning methods or for methods that perform activities that can be categorized as "fire and forget." However, you should return a Task wherever possible, because a void-returning
  async method can't be awaited. Any caller of such a method must be able to continue to completion without waiting for the called async method to finish, and the caller must be independent of any values or exceptions
  that the async method generates.

  The caller of a void-returning async method can't catch exceptions that are thrown from the method, and
  such unhandled exceptions are likely to cause your application to fail. If an exception occurs in an async method that returns a Task or Task<TResult>,
  the exception is stored in the returned task, and rethrown when the task is awaited. Therefore, make sure that any async method that can produce an exception has a return type of Task or Task<TResult> and
  that calls to the method are awaited.