code: boolean unregisterConnection(ConnectionManager cm, ConnectionListener cl, Object c)
     {
        if (clToC != null && clToC.get(cl) != null)
        {
           List<Object> l = clToC.get(cl);
           return l.remove(c);
        }
  
        return false;
     }
docs: Unregister a connection
  @param cm The connection manager
  @param cl The connection listener
  @param c The connection
  @return True if the connection was unregistered, otherwise false