I quite like what CloudFlare has done here. There's a fourth way to resolve this, that works for the core use case, is less engineering, and was in production

I quite like what CloudFlare has done here. There's a fourth way to resolve this, that works for the core use case, is less engineering, and was in production 20 years ago, but I can't fit it within the margins of this comment box. // CF's approach has additional feature advantages though.