A pointer to a RefString can be treated like a standard `char*` array by all code, but can additionally have
`g_ref_string_*()` methods called on it. `g_ref_string_*()` methods cannot be called on `char*` arrays not allocated using
RefString.
If using RefString with autocleanups, g_autoptr must be used rather than g_autofree,
so that the reference counting metadata is also freed.