private void dumpCache(Request req) {
        dispatchRpcRequest(req, () -> {
            final MemoryCache memoryCache = proxyServer.memoryCache();
            req.returnValues().add(new StringValue(memoryCache.dumpCacheToDisk(req.parameters().get(0).asString(), memoryCache)));
            req.returnRequest();
        });
    }
Returns 0 if server is alive.

@param req a Request
config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigProxyRpcServer.java