code: @SuppressWarnings("unchecked")
      @VisibleForTesting
      public static void resetGlobal() {
          tagsLock.writeLock().lock();
          try {
              tags.clear();
          } finally {
              tagsLock.writeLock().unlock();
          }
  
          resetNamespaces();
      }
docs: Remove all exported variables (including those from child namespaces).
  Also removes variables exported to a parent namespace.
  Not recommended for use outside of tests.