Log metrics for tensorboard

[rlouf]

It would be nice to be able to monitor the progress of sampling in real time. Totally do-able either using a callback and/or by logging every X steps when using "generate".

[ahartikainen]

Hi, I think you could be interested in developing this https://github.com/arviz-devs/arviz_dashboard

See the wiki.

[rlouf]

This looks very interesting, I will have a look!