private Operation buildOperation(OperationStatus st, OperationCallback cb,
    final String [] supportedMechs) {
    if (st == null) {
      return opFact.saslAuth(supportedMechs,
          node.getSocketAddress().toString(), null,
          authDescriptor.getCallback(), cb);
    } else {
      return opFact.saslStep(supportedMechs, KeyUtil.getKeyBytes(
          st.getMessage()), node.getSocketAddress().toString(), null,
          authDescriptor.getCallback(), cb);
    }
  }
If the total AUTH steps take longer than this period in milliseconds, a
warning will be issued instead of a debug message.
src/main/java/net/spy/memcached/auth/AuthThread.java