public int count(String node) {
        Deque<NetworkClient.InFlightRequest> queue = requests.get(node);
        return queue == null ? 0 : queue.size();
    }
Return the number of in-flight requests directed at the given node
@param node The node
@return The request count.
clients/src/main/java/org/apache/kafka/clients/InFlightRequests.java