I don't see `getRpc` method here. It's somewhat similar to `getRest`. See a sample here: https://go-endpoints.appspot.com/_ah/api/discovery/v1/apis/greeting/v1/rpc

Clients for some platforms actually use RPC instead of REST. For instance, iOS client always uses RPC. And (if I'm not mistaken, too lazy to check right now) JS client also "prefers" RPC but can to REST too.