Performance tab in DevTools takes 5x longer to show up compared to Timeline view in Observatory

[aam]

Dev tools peformance tab takes over 10 seconds to load, compared to just 2 seconds for observatory

launch-performance-tab-devtools.webm

observatory-timeline-launch.webm

This is on a simple dart app:

$ cat i1.dart
main() {
  Future.delayed(Duration(seconds :5), () { print('elapsed'); });

launched like

$ out/ReleaseX64/dart  --observe:8080 --disable-service-auth-codes --timeline_streams=all --timeline-recorder=endless --serve-observatory i1.dart

Devtools app launched separately, connected to this dart app paused.

[polina-c]

@kenzieschmoll