Method to determine whether the given input is a MasterPlaylist or MediaPlaylist

[Luro02]

This would be relatively simple to do;

pub enum Playlist {
    Master(MasterPlaylist),
    Media(MediaPlaylist),
}

impl TryFrom<&str> for Playlist {
    type  Error = Error;

    fn try_from(input: &str) -> Result<Self, Self::Error> {
        match MasterPlaylist::try_from(input) {
            Ok(v) => Ok(Self::Master(v)),
            Err(e) => {
                if e.is_unexpected_tag() {
                    match MediaPlaylist::try_from(input) {
                        Ok(v) => Ok(Self::Media(v)),
                        Err(e) => {
                            if e.is_unexpected_tag() {
                                Err(Error::custom("failed to determine playlist type"))
                            } else {
                                Err(e)
                            }
                        }
                    }
                } else {
                    Err(e)
                }
            }
        }
    }
}

one might have to do some adjustments to the above code, like maybe remove the nesting to improve readability?

The documentation should mention that one most likely gets a MasterPlaylist initially and that this method is quite inefficient, because it would have to parse a MediaPlaylist and a MasterPlaylist in the worst case.