code: function using(resourceFactory, observableFactory) {
      return new _Observable__WEBPACK_IMPORTED_MODULE_0__["Observable"](function (subscriber) {
          var resource;
          try {
              resource = resourceFactory();
          }
          catch (err) {
              subscriber.error(err);
              return undefined;
          }
          var result;
          try {
              result = observableFactory(resource);
          }
          catch (err) {
              subscriber.error(err);
              return undefined;
          }
          var source = result ? Object(_from__WEBPACK_IMPORTED_MODULE_1__["from"])(result) : _empty__WEBPACK_IMPORTED_MODULE_2__["EMPTY"];
          var subscription = source.subscribe(subscriber);
          return function () {
              subscription.unsubscribe();
              if (resource) {
                  resource.unsubscribe();
              }
          };
      });
  }
docs: PURE_IMPORTS_START _Observable,_from,_empty PURE_IMPORTS_END