@timneutkens I think this is ready for a review.
I've made some changes to the original design that _seem_ to have paid off. The parenting relationships for traces of normal builds are applied more uniformly, resulting in more intelligible traces:
<img width="900" alt="Screen Shot 2021-01-29 at 12 53 47 AM" src="https://user-images.githubusercontent.com/5016978/106253732-ba321880-61cc-11eb-98fd-d45af5078273.png">
Hot-reloading is surfaced now, too. I will note, however, that we will want to dig in deeper and find out where the large portion of time at the beginning of hot-reload is spent. Example:
<img width="894" alt="Screen Shot 2021-01-29 at 12 53 28 AM" src="https://user-images.githubusercontent.com/5016978/106253828-e057b880-61cc-11eb-967d-46eaff31ecef.png">
Where did those 180 ms go? At the least, we can now track how long a hot-reload takes, and have a place to start with further investigation.
652a1e8915
