* rpc: Strip down the base RPC client interface.
Prior to this change, the RPC client interface requires implementing the entire
Service interface, but most of the methods of Service are not needed by the
concrete clients. Dissociate the Client interface from the Service interface.
- Extract only those methods of Service that are necessary to make the existing
clients work.
- Update the clients to combine Start/Onstart and Stop/OnStop. This does not
change what the clients do to start or stop. Only the websocket clients make
use of this functionality anyway.
The websocket implementation uses some plumbing from the BaseService helper.
We should be able to excising that entirely, but the current interface
dependencies among the clients would require a much larger change, and one
that leaks into other (non-RPC) packages.
As a less-invasive intermediate step, preserve the existing client behaviour
(and tests) by extracting the necessary subset of the BaseService
functionality to an analogous RunState helper for clients. I plan to obsolete
that type in a future PR, but for now this makes a useful waypoint.
Related:
- Clean up client implementations.
- Update mocks.