Executing a Policy, I've see some people call ExecuteAsync like this:
...
.ExecuteAsync(async (ct) => await GetEmployeeAsync(employeeId, ct), cancellationToken);
And like this:
...
.ExecuteAsync(ct => GetEmployeeAsync(employeeId, ct), cancellationToken);
What is the difference and which one should be used?
In this simple case, there's no semantic difference. The version eliding async and await has an almost-immeasurable performance benefit.
In the general case, there are some pitfalls when eliding async and await. As a general rule, if the code does anything non-trivial, then you should keep the async and await. Only elide the async/await if the code is truly trivial - like in this case, when the delegate just binds employeeId on GetEmployeeAsync.