Replace Arc with Reference
This is just a suggestion...
It seems like there is a lot of unnecessary thread synchronization by having an
Glyph. We can replace
Arc with a reference to
Glyph and friends. There are downsides to this approach covered below (unless I missed something). But this is worth it in my opinion. Thread synchronization is a feature the user may choose to add themselves with
Arc or something else.
Glyphand friends cannot outlive
Fontis no longer
Fontenum variants' contents changed