Right, but I'm asking if FlatBuffers' approach to encoding is similar to Cap'n Proto. It seems like the answer is "yes", but I might be missing something.
Disclaimers:
1) I'm the author of Cap'n Proto; I'm probably biased.
2) A lot could have changed since 2014. (Though, obviously, serialization formats need to be backwards-compatible which limits the amount they can change...)