@Override
    public void shutdown() throws InterruptedException {
        initiateShutdown();
        networkClient.initiateClose();
        awaitShutdown();
        Utils.closeQuietly(networkClient, "InterBrokerSendThread network client");
    }
An inter-broker send thread that utilizes a non-blocking network client.
server-common/src/main/java/org/apache/kafka/server/util/InterBrokerSendThread.java