Assuming UTF-8 is not compatible with Quake 1 maps

[dsvensson]

Anything from worldspawn message (map name) to entity messages may be encoded in for example "red" text, so treating the .map file as UTF-8 is inherently invalid. It needs to be Vec<u8> and while entity key names are always valid ascii, the values are not. Ideally shalrath would consider property values as variable, and have some support for parsing origin, angles and other common fields in a structured manner.

qmap for examples deals with this by using CString for both key and value https://github.com/4LT/quake-util/blob/master/src/qmap/repr.rs#L152 which is by convention kind of useless as I think it's unheard of that keys would have weird chars.