RFC: performance benchmarking scenarios

[coolsoftwaretyler]

We want to improve the performance of MobX-State-Tree. But before we can solve the problem, we need to observe and understand the problems.

To that end, if you have ever experienced poor MST performance, we'd love to hear about your specific use case so we can reproduce it and benchmark it.

The more actual code you can provide, the better. If possible, please send us a code sandbox with your problem code (or a reproduction of it), along with a write up of what behavior is problematic and how so.

We'll use these code samples to begin writing more performance benchmarking tests so we can diagnose any problems and verify potential solutions.

Thanks!

[coolsoftwaretyler]

Here's a scenario we can model: #2087

[coolsoftwaretyler]

Perhaps there's a deeper story behind this PR: #2084

[coolsoftwaretyler]

I'm feeling pretty good about our tools for measuring performance. If you have a scenario, will you please submit a PR to the performance suite?

https://github.com/coolsoftwaretyler/mst-performance-testing

[coolsoftwaretyler]

Gotta add this one: #2128