private static void completeWithDisconnect(
        ClientRequest request,
        long now,
        AuthenticationException authenticationException
    ) {
        final RequestCompletionHandler handler = request.callback();
        handler.onComplete(
            new ClientResponse(
                request.makeHeader(request.requestBuilder().latestAllowedVersion()),
                handler,
                request.destination(),
                now /* createdTimeMs */,
                now /* receivedTimeMs */,
                true /* disconnected */,
                null /* versionMismatch */,
                authenticationException,
                null
            )
        );
    }
An inter-broker send thread that utilizes a non-blocking network client.
server-common/src/main/java/org/apache/kafka/server/util/InterBrokerSendThread.java