I don't see much point of creating a one line external function to avoid repeating one line call to the final callback

we would end up using something like:
```javascript
function sendError(error, finalCallback) {
  finalCallback({
    'reason': error
  }, 0, error.message);
}
...
if (error) {
  sendError(error, finishCallback);
  return;
}
```

but if you still think this is better, I can live with it :)