I'm looking for documentation or just detailed description in some form of fabric protobuf structure and usage. Nodes communicate to each other using GRPC, but it's not clear what exactly they sending to each other? Blocks and transactions also stored in protobufs inside level db, i need to know which protobufs should i use to decode blocks. Of course it's possible to reverse engineer all that, but it takes a lot of time. Maybe this docs right now is not well formatted/not ready to be published in official docs, but it would be great to have them even in draft form. Thanks in advance!