Custom datetime format

[max-sixty]

Would you take a PR that allowed for passing a datetime string in the ProgressBar format?

Would cover #71 and more

I'm not sure exactly how it would fit with the format string. We could add it as an additional argument after the style argument; e.g. if were named elapsed_chrono

{spinner:.green} [{elapsed_chrono:.blue.%s:%ff}] [{bar:40.cyan/blue}] {bytes} ({eta})

...but is that too large an API change for the benefit?

[mitsuhiko]

Yep, would accept a PR.

[djc]

I think this is currently possible using custom formatters.