code: public UserScenario getUserScenario(int id) {
          return invoke(USER_SCENARIOS, id,
                  new RequestClosure<JsonObject>() {
                      @Override
                      public JsonObject call(Invocation.Builder request) {
                          return request.get(JsonObject.class);
                      }
                  },
                  new ResponseClosure<JsonObject, UserScenario>() {
                      @Override
                      public UserScenario call(JsonObject json) {
                          return new UserScenario(json);
                      }
                  }
          );
      }
docs: Retrieves a user scenario.
  
  @param id its id
  @return {@link com.loadimpact.resource.UserScenario}