To be even fair-er, it wasn't actually memory unsafety, it was "just" unsoundness, there was a type, that IF you gave it an io reader implementation that was we

To be even fair-er, it wasn't actually memory unsafety, it was "just" unsoundness, there was a type, that IF you gave it an io reader implementation that was weird, that implementation could see uninit data, or expose uninit data elsewhere, but the only readers actually used were well behaved readers.