docs: public static boolean areRequestHeadersValid(HeaderMap headers) {
          HeaderValues te = headers.get(Headers.TRANSFER_ENCODING);
          HeaderValues cl = headers.get(Headers.CONTENT_LENGTH);
          if(te != null && cl != null) {
              return false;
          } else if(te != null && te.size() > 1) {
              return false;
          } else if(cl != null && cl.size() > 1) {
              return false;
          }
          return true;
      }