message: Back out "TimeseriesPolymorphicWrapper: remove always-empty args pack from the constructor"
  Summary:
  Breaks build on Windows
  Original commit changeset:
  Original Phabricator Diff: (https://github.com/facebook/fb303/commit/c293d383cf86709e7cc873104aed593016a72c43)
diff: @@ -898,9 +898,12 @@ class TimeseriesPolymorphicWrapper : public TimeseriesWrapperBase {
  : TimeseriesWrapperBase(varname) {
  exportStats(arg1, args...);
  }
  - explicit TimeseriesPolymorphicWrapper(const std::string& key)
  + template <typename... Args>
  + explicit TimeseriesPolymorphicWrapper(
  + const std::string& key,
  + const Args&... args)
  : TimeseriesWrapperBase(key) {
  - exportStats();
  + exportStats(args...);
  }
  protected:
  