EB doesn't load as quick

I understand that the new error experience just released not too long ago, but it can't keep up with the mistakes I make in my code. You should try fixing that problem. Thanks!

The issue names no files, tests, or entry points. Start by reproducing the slow error experience in the browser-based live editor, then trace the relevant loading path and measure it; done means the new error experience keeps up with rapid coding mistakes without regressions.

Written by the indexing model from the issue text.