A 'connection_state Implementation.t is something that knows how to respond to one query, given a 'connection_state. That is, you can create a 'connection_state Implementation.t by providing a function which takes a query *and* a 'connection_state and provides a response.

A 'connection_state Implementations.t is something that knows how to respond to many different queries. It is conceptually a package of 'connection_state Implementation.ts.

A state rpc is an easy way for two processes to synchronize a data structure by sending updates over the wire. It's basically a pipe rpc that sends/receives an initial state of the data structure, and then updates, and applies the updates under the covers.

An RPC that has no response. Error handling is trickier here than it is for RPCs with responses, as there is no reasonable place to put an error if something goes wrong. Because of this, in the event of an error such as dispatching to an unimplemented RPC, the connection will be shut down. Similarly, if the implementation raises an exception, the connection will be shut down.