see more from https://github.com/openzipkin/brave/issues/867, also see https://github.com/apache/incubator-dubbo/issues/3576
if (StringUtils.isEmpty(host)) {
            return getLocalHost();
        }
        return host;
    }
    /**
     * set remote address.
     *
     * @param host
     * @param port
     * @return context
     */
    public RpcContext setRemoteAddress(String host, int port) {
        if (port < 0) {
            port = 0;
        }
        this.remoteAddress = InetSocketAddress.createUnresolved(host, port);
        return this;
    }
    /**
     * get remote address.
     *
     * @return remote address
     */
    public InetSocketAddress getRemoteAddress() {
        return remoteAddress;
    }
    /**
     * set remote address.
     *