public boolean hasRequests() {
            for (ConcurrentLinkedQueue<ClientRequest> requests : unsent.values())
                if (!requests.isEmpty())
                    return true;
            return false;
        }
Return whether the caller is still awaiting an IO event.
@return true if so, false otherwise.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/ConsumerNetworkClient.java