public void putProtocol(Protocol protocol) {
        if (protocols.put(protocol.getName(), protocol) != null) {
            clearPolicyCache();
        }
    }
Registers a protocol with this repository. This will overwrite any protocol that was registered earlier that has
the same name. If this method detects a protocol replacement, it will clear its internal routing policy cache.

@param protocol The protocol to register.
messagebus/src/main/java/com/yahoo/messagebus/ProtocolRepository.java