void concurrent_server_handler::on_fail (connection_ptr con)
 {
     if(m_coordinator) {
         m_coordinator->add_event(new websocketConnectionEventFail(con));
     } else {
         websocketConnectionEventFail(con).triggerEvent();
     }
     
     int deletes = m_connections.erase(con);
     
     con->elog()->at(websocketpp::log::elevel::INFO) << "on_fail deleted "
     << deletes << " connections." << websocketpp::log::endl;
     
 }