public MessageBusParams setProtocolConfigId(String configId) {
        protocolConfigId = configId;
        return this;
    }
Sets the id to resolve to protocol config. This has a proper default value that holds for Vespa applications,
and can therefore be left usnet.

@param configId The config id.
@return This, to allow chaining.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/MessageBusParams.java