private void interruptOldAuth(MemcachedNode nodeToStop) {
    AuthThread toStop = nodeMap.get(nodeToStop);
    if (toStop != null) {
      if (toStop.isAlive()) {
        getLogger().warn(
            "Incomplete authentication interrupted for node " + nodeToStop);
        toStop.interrupt();
      }
      nodeMap.remove(nodeToStop);
    }
  }
Interrupt all pending {@link AuthThread}s.

While shutting down a connection, if there are any {@link AuthThread}s
running, terminate them so that the java process can exit gracefully (
otherwise it will wait infinitely).
src/main/java/net/spy/memcached/auth/AuthThreadMonitor.java