Make `_convert_time` public and add funtionalities

[priba]

trafficstars

🚀 Feature Request

Allow Time conversions

Motivation

For custom callbacks, it would be nice to expose _convert_time in the API.

Hopefully, it is expose _convert_time in the API. That is _convert_time -> convert_time. And add the conversion type.

I am happy to start a PR about that