Timeout error returns non-valid Javascript object

Maybe I am missing something here. But here is what I see in the err argument for a call that times out:

```
call.end(function(err, response) {
console.log(err); // { [Error: timeout of 1ms exceeded] timeout: 1 }
console.log(JSON.stringify(err)); // {"timeout":1}
console.log(typeof err); // object
```

It seems like the error message is somehow getting tacked onto the err object w/o a proper key?