private void drainGeneratedRequests() {
        generateRequests().forEach(request ->
            unsentRequests.put(
                request.destination,
                networkClient.newClientRequest(
                    request.destination.idString(),
                    request.request,
                    request.creationTimeMs,
                    true,
                    requestTimeoutMs,
                    request.handler
                )
            )
        );
    }
An inter-broker send thread that utilizes a non-blocking network client.
server-common/src/main/java/org/apache/kafka/server/util/InterBrokerSendThread.java