code: function freeParser(parser, req) {
    if (parser) {
      parser._headers = [];
      parser.onIncoming = null;
      if (parser.socket) {
        parser.socket.onend = null;
        parser.socket.ondata = null;
        parser.socket.parser = null;
      }
      parser.socket = null;
      parser.incoming = null;
      parsers.free(parser);
      parser = null;
    }
    if (req) {
      req.parser = null;
    }
  }
docs: Free the parser and also break any links that it might have to any other things. TODO: All parser data should be attached to a single object, so that it can be easily cleaned up by doing `parser.data = {}`, which should be done in FreeList.free.  `parsers.free(parser)` should be all that is needed.