@Override
    public void close(String nodeId) {
        log.info("Client requested connection close from node {}", nodeId);
        selector.close(nodeId);
        long now = time.milliseconds();
        cancelInFlightRequests(nodeId, now, null, false);
        connectionStates.remove(nodeId);
    }
Closes the connection to a particular node (if there is one).
All requests on the connection will be cleared.  ClientRequest callbacks will not be invoked
for the cleared requests, nor will they be returned from poll().

@param nodeId The id of the node
clients/src/main/java/org/apache/kafka/clients/NetworkClient.java