The protocol comes from Pantor Engineering, which apparently provides an "advanced trading system" out of Stockholm. Neat.
http://blog.blinkprotocol.org/2013/01/blink-compared-to-goog...
As you can see in a comment by Rolf, part of the perf limitation of GPB is the implementation and not the wire protocol.
Anders
From the docs:
"You should be very careful about marking fields as required. If at some point you wish to stop writing or sending a required field, it will be problematic to change the field to an optional field – old readers will consider messages without this field to be incomplete and may reject or drop them unintentionally. You should consider writing application-specific custom validation routines for your buffers instead. Some engineers at Google have come to the conclusion that using required does more harm than good; they prefer to use only optional and repeated. However, this view is not universal."