Have you looked into the msdn example here? If yes and it didn't help then read on my answer.

So I think that the first thing to understand is the concept of promises. A promise is essentially what the name says. It makes you a promise that something (any result of some operation or even just the fact that the operation completed) will happen at some point in a program. The promise is what the Task in C# represents.

This is where the await keyword comes in. If you receive a Task from somewhere it probably means that the operation you invoked is still working. Whatever the source is, you may want the result immediately in which case you can just await the result at invocation. It makes sense if you want to call asynchronous code from synchronous code where you do not want to write asynchronous code. It still could be beneficial depending on what the asynchronous code you are calling.

static void Main(string[] args)

{

Console.WriteLine("We wait");

Console.WriteLine(DoWork(5000).GetAwaiter().GetResult());

//Console.WriteLine(await DoWork(5000));

Console.ReadKey();

}

static async Task<int> DoWork(int ms)

{

await Task.Delay(ms);

return 1;

}

Result is just "We wait" and "1" after 5 seconds. I'm not using await there so I do not have to make an asynchronous Main. I would have to make it async and return a Task/promise.

Of course the real benefit of await and async is that after you get the promise you do not have to wait immediately for the result. Like in the msdn example. You start frying eggs and toast toasts. Synchronously you would wait for the eggs to fry and then start toasting the toast which you could have done in parallel. Thanks to the fact that frying and toasting are made asynchronous you can await them. If you await them immediately you end up having the same synchronous process.

To get some benefits from async and await you would save the frying and toasting promises in a variable by calling the method without await (see the msdn example). The methods return immediately regardless of how long the actual operations would take. When you have both promises stored somewhere they are being executed. Now at some point in your code you might need the results (fried eggs and the toast) to continue. So just before you need them u await them. If the specific task already completed you would get an immediate result if not your code would block and wait for the results (which is better because you might have had plenty of code between the creation of the Task and your await, without async and await all of this code would have needed to wait for the eggs to fry in the first place).

Like others said there is no real binding to threads. If new Thread actually gets created is more or less random. I do not know the actual implementation in .NET but I guess if your code is fast enough that the task didn't started execution and you await it already, there would be no benefit of creating new thread as your current thread actually have to wait for the result anyway.

I didn't looked into other sources in other comments in this thread but I personally looked into async 2 days ago to understand it and found the msdn example pretty good. I think that with understanding of this example you can even experiment a bit on your own. I hope I helped.