docs: private void removeHdrInstances(HeaderElement root, boolean bFilter) {
          if (null == root) {
              return;
          }
          HeaderKeys key = root.getKey();
          if (bFilter && key.useFilters()) {
              filterRemove(key, null);
          }
          HeaderElement elem = root;
          while (null != elem) {
              elem.remove();
              elem = elem.nextInstance;
          }
      }