docs: public <T> Single<PollingState<T>> pollSingleAsync(final PollingState<T> pollingState, final Type resourceType) {
          if (pollingState.initialHttpMethod().equalsIgnoreCase("PUT")
                  || pollingState.initialHttpMethod().equalsIgnoreCase("PATCH")) {
              return this.pollPutOrPatchSingleAsync(pollingState, resourceType);
          }
          if (pollingState.initialHttpMethod().equalsIgnoreCase("POST")
                  || pollingState.initialHttpMethod().equalsIgnoreCase("DELETE")) {
              return this.pollPostOrDeleteSingleAsync(pollingState, resourceType);
          }
          throw new IllegalArgumentException("PollingState contains unsupported http method:" + pollingState.initialHttpMethod());
      }