fn single_subst1(
ctx: &mut hb_ot_apply_context_t<'_>,
external_cache: &SubtableExternalCache,
table_data: &[u8],
) -> Option<()>fn single_subst1(
ctx: &mut hb_ot_apply_context_t<'_>,
external_cache: &SubtableExternalCache,
table_data: &[u8],
) -> Option<()>