Creating a task wrapper around an existing object

Question

I have a method which returns a Task where the implementation may or may not need to perform a slow operation in order to retrieve the result. I would like to be able to si

Answer 1

You could use a TaskCompletionSource:

var tcs = new TaskCompletionSource();
tcs.SetResult(_Cache[key]);
return tcs.Task;

(Note that if _Cache is a Dictionary you could use TryGetValue to make it a single lookup.)