[tijsvd]

> No zero-copy for networking? Forced internal heap allocations with only this arena feature after a decade? Sorry no. Protobufs isn't useful for serious network applications.

That's a bit harsh. Protobufs deliver smaller wire size than any of the newer "zero-copy" formats. And many receivers of zero-copy formats will... copy the data into some internal representation. If your protobuf implementation delivers classes that are good enough to work with internally (store in maps, forward, etc) then you don't really lose something; instead you gain, due to no manual conversion layer.

[jasonzemos]

CBOR also delivers optimal wire sizes with its variable length encoding. Ceteris paribus, there's no technical advantage to using protobufs. The choice is almost always non-technical (business, platform, partnership, etc) or simple naivete. It's not harsh, it's just engineering.