OwnedValueAccessor relies on raw, manually annotated 'owned' flags to be passed around, e.g. here:

    void reset(TypeTags tag, Value val) {
        reset(true, tag, val);
    }
    void reset(bool owned, TypeTags tag, Value val) override {
        release();
        _tag = tag;
        _val = val;
        _owned = owned;
    } 

This task is to
(1) Introduce overloads of reset() which take an TagValueOwned, TagValueMaybeOwned and TagValueView
(2) Rename the existing reset() interfaces to reset_raw()
(3) Remove as many reset_raw() calls as possible, replacing them with reset()

(3) will likely be a very large change that we'll have to split across multiple tickets.

If feasible, we should eliminate the reset(TypeTags, Value) overload completely and replace it with either reset_raw(true, tag, val), or, preferably, one of the new reset() overloads which takes an RAII type.