GRPC will attempt to lookup resolvers from this registry based on the scheme used in target uris passed to the channel builder. This registration could be done by adding a META-INF service location file to the classpath. However given we sometimes get packaged in interesting ways it may be simpler to just register our provider at runtime. This must be called before using any multi-host uris (and ideally called only once).

As we have many hosts it would be awfully clunky to encode them into a single URI. Instead cache the hosts in memory and generate a unique id for this configuration that can be sensibly put into a URI then loaded from cache if used.