Unhandled stream error in transformStream

From reading code example, it is using lazypipe as transformStream, but lazypipe can only attach error listener after it is initialized. So I guess there is no way to capture transformStream's error in our gulpfile.

My situation is running a watch task for babel transformStream, once babel throw error a syntax error, it will exit the watch process, here is a short code example:

```
return gulp.src('./www/index.html')
.pipe(plugins.useref(
{},
lazypipe().pipe(function () {
return plugins.babel()
.on('error', onError);
})；
))；
```

In this case my onError won't end the transformStream as I wish.
My question is if we can add `on('error')` on those transformStream by default to `emit('end')` and let gulpfile handling the error itself. I would also appreciate any suggestion for how to handle this?

Thanks.