VM Tools page has several bugs when debugging a Flutter test

[kenzieschmoll]

Repro: run a flutter test with flutter test test/foo_test.dart --start-paused. Copy the VM service URI and connect to DevTools.

bugs:

• data doesn't load on initial selection of vm tabs. If it is waiting on something, there is no indicator
• switching isolates or clicking refresh throws exceptions
• the page feels generally broken, difficult to trust the state

@bkonyi

[bkonyi]

What sub-tool is this related to? What exceptions are you seeing?

The VM screen seems fine, but the Isolate tab does seem to have some lag. I think all of these sub-tools are being built whether or not they're actively being displayed, which could be causing some performance issues, especially since it seems that switching tools causes a rebuild triggering each controller to be reinitialized.