@Override
    public void run() {
        if (rpcServer != null) {
            Thread t = threadFactory.newThread(rpcServer);
            t.setName("RpcServer");
            t.start();
        }
    }
A proxy server that handles RPC config requests. The proxy can run in two modes:
'default' and 'memorycache', where the last one will not get config from an upstream
config source, but will serve config from memory cache only.

@author hmusum
config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ProxyServer.java