I believed any kind of asynchronous execution makes a thread in invisible area. But if so,
- Async codes does not offer any performance gain than threaded codes.
But I can’t understand why so many developers are making many features async form.
Could you explain about difference and cost of them?
The purpose of an asynchronous execution is to prevent the code calling the asynchronous method (the foreground code) from being blocked. This allows your foreground code to go on doing useful work while the asynchronous thread is performing your requested work in the background. Without asynchronous execution, the foreground code must wait until the background task is completed before it can continue executing.
The cost of an asynchronous execution is the same as that of any other task running on a thread.
Typically, an async result object is registered with the foreground code. The async result object can either raise an event when the background task is completed, or the foreground code can periodically check the async result object to see if its completion flag has been set.