These are the cases where an interface returns Task, but our
implementation is synchronous. In these cases we prefer to declare the
method as async and suppress, because this keeps the exception semantics
the same as a 'true' async method.
This doesn't add any new extensibility, and will likely change again in
the future when we add extensibility. For now this is a stopgap to reduce
duplication between JsonResult and JsonViewComponentResult.
Yishai Galatzer
Ryan Nowak