Cap'n Proto 1.0
While I never used Cap&#x27;n Proto, I want to thank kentonv for the extremely informative FAQ answer [1] on why required fields are problematic in a protocol<p>I link it to people all the time, especially when they ask why protobuf 3 doesn&#x27;t have required fields.<p>[1] <a href="https:&#x2F;&#x2F;capnproto.org&#x2F;faq.html#how-do-i-make-a-field-required-like-in-protocol-buffers" rel="nofollow noreferrer">https:&#x2F;&#x2F;capnproto.org&#x2F;faq.html#how-do-i-make-a-field-require...</a>