C# Async Task Method Without Await or Return

Question

I have an Interface I that is implemented in two places like:

interface I 
{ 
   Task DoSomething();
}

The interface has async Task DoSomet

Answer 1

I see that most people prefer to leave out the async and use Task.ComletedTask instead. But even if await is not used, there is still a big difference in exception handling

Consider the following example

static async Task Main(string[] args)
{

    Task task = test(); // Will throw exception here
    await task;

    Task taskAsync = testWithAsync();
    await taskAsync; // Will throw exception here
}

static Task test()
{
    throw new Exception();
    return Task.CompletedTask; //Unreachable, but left in for the example
}

static async Task testWithAsync()
{
    throw new Exception();
}

Using

test().ContinueWith(...); or Task.WhenAll(test())

may result in unexpected behaviour.

Therefore, I prefer async instead of Task.CompletedTask or Task.FromResult.