[Feature Request] Improve callback graph

[jjaraalm]

Right now the callback graph is somewhat useful for identifying logical flow issues, but I think it could be greatly improved if it could be dynamic rather than static.

Possible improvements

• Zoom in/out functionality for large/complex callback chains
• Callback graph accessible from a dedicated url (maybe this already exists?) in addition to an overlay so that you can do test interactions while examining the callback graph
• Distinguish between clientside and serverside callbacks using different node colors.
• Report profiling information
  • Number of times a callback was invoked per node
  • Time spent (total or average) in the callback. Maybe link to the node color?
  • Label each edge with the number of times that input triggered a callback
• Live debugging
  • Highlight currently executing callbacks and modified outputs
  • Probe the last input/output by hovering/focusing an edge

For live debugging, I'm thinking something similar to the Labview execution highlighting if you've ever used it. When you turn on debugging mode, callbacks intentionally get a delay injected into them to slow everything down so you can visually watch and inspect the logical flow. Like this:

[gvwilson]

Hi - we are tidying up stale issues and PRs in Plotly's public repositories so that we can focus on things that are most important to our community. If this issue is still a concern, please add a comment letting us know what recent version of our software you've checked it with so that I can reopen it and add it to our backlog. (Please note that we will give priority to reports that include a short reproducible example.) If you'd like to submit a PR, we'd be happy to prioritize a review, and if it's a request for tech support, please post in our community forum. Thank you - @gvwilson