Would be interesting if someone who has managed to run it tries it on some actually complicated text layout edge cases (like RTL breaking that splits a ligature necessitating re-shaping, also add some right-padding in there to spice things up).
[1] https://github.com/wilsonzlin/fastrender/blob/main/src/layou...
[2] https://github.com/wilsonzlin/fastrender/blob/main/src/layou...
[3] Neither being the right place for defining a struct that should go into computed style imo.