Ok, now that gives a very different picture from what the original comment explained. Of course, protobuf to flatbuffer is slower than just protobuf...

Thanks a lot for your time (and work!). FYI, i'm planning on using flatbuffer for communication between a mobile app native code and a cross-platform library, hoping to save on data decoding time. A bit similar to what Xi ide is doing. If you have any advice, you're welcome ! :D