If called from an appropriate context, creates an event-driven promise that will resolve asynchronously when the request is complete.
set_promise_context(x, ctx)The object ‘x’.
a 'recvAio' object returned by request or
request_signal.
the context environment.
The object passed as ‘x’ is returned regardless of whether the promise context was set successfully or not. If successful, ‘x’ is modified in place with the promise context.