C# Fire and Forget 任务并丢弃

Question

I need to do a fire and forget call to some async method. I realised VS is suggesting that I can set the call to a _discard and the IDE warning goes away. But I'm not sure if that call is still not awaited when used with the discard. Would it be?

 public async Task<object> SomeSideTaskToBeForgotten()
 {
     ...blah blah
 }

 public async Task MainTask()
 {
     ..some stuff
     _ = SomeSideTaskToBeForgotten(); //is this still fire and forget?
     ..some other stuff
 }

Answer 1

Yes, it's still fire and forget.

When SomeSideTaskToBeForgotten(); returns a Task , the remainder of your method will execute, without waiting for the Task to complete.

The discard just makes explicit the fact that the Task isn't required for any further processing.

VS will be recommending the discard because SomeSideTaskToBeForgotten(); returns something ie not void.

Answer 2

Or you could just call it like the following and pragma out the warnings if you need.

SomeSideTaskToBeForgotten();

_{Just a side note : nothing suggested here (no unobserved task) is truly fire and forget until you catch your exceptions inside of SomeSideTaskToBeForgotten . The reason why is, if an exception is thrown on an unobserved task, the error is placed on the task and can be rethrown at unexpected times. You wont be forgetting it as its likely to exception you out of your application. Just saying :)}