docs: @Override
      public boolean validForHeader(HeaderKeys hdr, boolean includesDollar) {
          // Cookie headers need the $ symbol
          if (HttpHeaderKeys.HDR_COOKIE.equals(hdr) || HttpHeaderKeys.HDR_COOKIE2.equals(hdr)) {
              return includesDollar;
          }
          // Set-Cookie headers do not
          if (HttpHeaderKeys.HDR_SET_COOKIE.equals(hdr) || HttpHeaderKeys.HDR_SET_COOKIE2.equals(hdr)) {
              return !includesDollar;
          }
          return false;
      }