Callback for time left in generating speech with `tts.predict`

[C-Loftus]

Hi! Thank you for making this library. It is very useful. I am trying to think about ways to improve UX for speaking longer blocks of text.

• I was wondering if it would be possible to add a progress callback for how long it will take to complete an inference instead of just having a callback for downloading.
  • (i.e. progress.secondsLeftApprox , progress.bytesLeft or something analogous).
  • Without a feature like this, it is harder for users to know if a long generation time is expected or due to a bug

If you have other ideas that might be better, please don't hesitate to let me know or push me towards other directions. I would be happy to submit a PR for a feature like this.
Thank you

[raymondtri]

I believe there are too many factors to really make this possible. However, you can give a rough approximation (and improve performance in long blocks of text) by breaking things into paragraphs / sentences and then invoking over that. As they complete you can get some idea of how many characters have been processed and the speed at which translation is happening in order to estimate completion.