Add a buffering state

[alecgorge]

This might take a bit of adjustment to the classes, can state be added to indicate that the underlying source is buffering?

This would be particularly useful for the HTTPSource.

[alecgorge]

To clarify, this state would occur when playback has stopped because the engine is waiting for more data from the source

[daria-kopaliani]

+1, adding buffering state could also be helpful in solving "can not pause in the beginning" issue

[ap4y]

Hey guys, sorry I don't think I will be able to help you with adding this new feature. You probably noticed I'm not super active lately in this project. Mostly because I'm a bit busy lately and have some other OSS project I want to work on. I also don't use this engine as much, I prefer listening to vinyl LPs this days. I can give write access to the repository if someone wants. Also forking is always a good option with MIT license. I will try to help by answering the questions (send me an email) and fixing bugs, but I don't plan to add new features or make major code changes.