code: function(_key,_type){
              var _request = _cache[_key];
              if (!_request) return;
              var _callback = _request[_type],
                  _args = _r.slice.call(arguments,2);
              try{
                  (_callback||_f).apply(null,_args);
              }catch(ex){
                  // ignore
                  if (DEBUG) throw ex;
                  console.error(ex.message);
                  console.error(ex);
              }
              _doClear(_key);
          }
docs: request callback