Node.js and error parsing a protocol buffer

Below is my code for trying to parse a protocol buffer from node.js. It works in python but in node.js I seem to be having issues. My big concern is am 1) am i getting the payload correct? and 2) Am I using protocol buffers to parse the payload correct.

When I log to the console the payload is sys so I am assuming that s the prot buffer from the request. Then I parse the buffer by calling:

 bid_request.parse(payload);

Here is the code snippet and error:

var buffertools = require('buffertools');
var Schema = require('protobuf').Schema; 
var schema = new Schema(fs.readFileSync('/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/test.desc'));

app.post('/n/test', function(req, res){

      var payload = [];
      req.on('data', function (data) {
        payload.push(data);
      });
      console.log(payload);
      req.on('end', function () {
        var payload = buffertools.concat.apply(null, payload);
        console.log(payload);
        console.log('--------------');
        var bid_request = schema['BidRequest'];

        var brr_fu = bid_request.parse(payload);

        // rest of code here

      });

});


libprotobuf ERROR google/protobuf/message_lite.cc:123] Can't parse message of type "BidRequest" because it is missing required fields: id

undefined:1
urn f.call(self,
      ^
Error: Malformed message
    at Function.parse (unknown source)
    at IncomingMessage.<anonymous> (/home/ubuntu/workspace/rtbopsConfig/rtbServers/rtbNodejsServer/bidder.js:80:31)
    at IncomingMessage.emit (events.js:64:17)
    at HTTPParser.parserOnMessageComplete [as onMessageComplete] (http.js:130:23)
    at Socket.ondata (http.js:1506:22)
    at TCP.onread (net.js:374:27)

I am also curious as to why the payload is a <SlowBuffer>