Currently our VTABLEs vary in a couple different aspects:

• some are static and others are non-static
• some are const and others are constexpr
• some are constructed with VTABLE = {...} and others with VTABLE{...}
• some explicitly name their parameters (e.g. .destroy = &_extDestroy) and others rely on the positioning of the arguments to match the corresponding members

We should check that there's valid reasons to the differences, and where possible standardize them. On the last point, we should always name the parameters.