Web-based workflow inspector.

[zach-klippenstein]

AC: The ability to tell adb to forward a port, point a web browser at it, and see a live view of what workflows are running, maybe even send them events.

Should share infrastructure with square/workflow#129.

[zach-klippenstein]

Stetho does exactly this, using the Chrome DevTools protocol. We can also use DevTools to stream this data. See this repo for the official protocol spec.

[rjrjr]

We have good internal support for Perfetto in the form of a WorkflowInterceptor. Should open source that.