Returning `{keyword_null}` from a non-`{keyword_async}` `Task`/`Task{typeparameter_TResult}` {concept_method} will cause a `NullReferenceException` at runtime if the {concept_method} is awaited. This problem can be avoided by returning https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task.completedtask[`Task.CompletedTask`] or https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task.fromresult[`Task.FromResult{typeparameter_TResult}({keyword_null})`] respectively.
