There are two types of parallelism you can do with MidWay, fan-out and pipeline.
In fan-out you call multiple services simultaneously. This is asynchronous request/response. In order do this, we use the mwacall() to issue the request and mwfetch() to get the response later.
In order to do pipelining you use mwforward() in the server to pass the request onto another service.
The first service may do something like user authentication, the second format checking, the third the actual DB interface, and the fourth formatting of reply.