Benchmarks

[rleungx]

It's good to see this project is open source right now. Recently, I did some simple benchmarks for comparing Marshal/Unmarshal in different implementations and I also added fastpb. See https://github.com/rleungx/benchmarks/tree/main/protobuf. Please let me know if I was using the right way to do these benchmarks.

[Hchenn]

Thanks, we'll look at it later.