True zero-copy is not achievable with Protobuf, you need something like FlatBuffers for that. What is presented here is more like a zero-allocations.
Is this still true? New versions of protobuf allow codegen of `std::string_view` rather than `const std::string&` (which forces a copy) of `string` and `repeated byte` fields.
I also find this misleading, and could be solved so easily by just explaining that of course varints need resolving and things will just happen lazily (presumably, I didn’t read the code) when they are requested to be read rather than eagerly.