code: @Override
    public Collection<SocketAddress> getUnavailableServers() {
      ArrayList<SocketAddress> rv = new ArrayList<SocketAddress>();
      for (MemcachedNode node : mconn.getLocator().getAll()) {
        if (!node.isActive()) {
          rv.add(node.getSocketAddress());
        }
      }
      return rv;
    }
docs: Get the addresses of unavailable servers.
  
  <p>
  This is based on a snapshot in time so shouldn't be considered completely
  accurate, but is a useful for getting a feel for what's working and what's
  not working.
  </p>
  
  @return point-in-time view of currently available servers