Can't use mutable header APIs after sent.

[Migrate]

Hi,

Thanks for writing this great plugin. I'm using it in several collections.

I'm also trying to use mongoose-types in a embedded document, but it does not work: The first sub-document is added without any problems but then I cannot add more sub-documents. I always get the following error:

http.js:543
throw new Error("Can't use mutable header APIs after sent.");

Here is the code:

//add tracker to account.

var Actor = mongoose.model('Actor');
function add_tracker(req, res, next) { 
    Actor.findById(req.params.id, function(err, actor) {
        if (err) {
            console.log(err);
        }
        var tracker_value = req.body.tracker.value;
        var tracker = { value: tracker_value };
        var trackers_size = actor.trackers.length;
        actor.trackers.push(tracker);
        actor.save(function(err){
            res.local("actor", actor);
            if (err) res.send({ error: err.message });
            var tracker = actor.trackers[trackers_size];
            res.partial('account/_tracker', { object: tracker }, function(err, html) {
              if (err) {
                  res.send({ error: err.message });
              } else {
                  res.send({ prepend: html, to: '#tracker_list' });
              }
            });
          })
    });
}

//database schema:

var mongoose = require('mongoose'), 
    mongooseTypes = require("mongoose-types"),
    useTimestamps = mongooseTypes.useTimestamps;

var Trackers = new Schema({
        value : String
 });
Trackers.plugin(useTimestamps);

var Actor = new Schema({
        , name     : String
        , trackers      : [Trackers]
});
mongoose.model('Actor', Actor);

If I remove mongoose-types from the embedded the error does not occur.

Thanks.
Best regards,
Migrate