Streamed service method calls for large payload using multiple requests

[kanghyojun]

To make a procedure call with a large payload, it should be called with a few small payloads which are divided from one large payload through several HTTP requests to get more availability of service. I think it might be helpful if both Nirum RPC service and a client can make an RPC with one large payload into several RPC with a small payload.

service customer-service (
    @stream(window=1000)
    customer cusomers ([uuid] customer-ids);
);

Since a service schema hardly knows proper size of a window, it is possible to give the information using annotation.