What's the usage scenario of this tool?

Hi All,

As title suggested, I am wondering if this package can do the following:
- Capture a stream of gRPC request and response through network packet capturing (assuming that the captured packets are purely from one gRPC connection between one server and one client).
- Feed the stream into this trans-coder. Would this trans-coder actually produces the corresponding json request and response directly?
- Or I need to extract the protocol buffer binary stream out of the gRPC stream and feed to this transcoder, which means that this transcoder does not handle the protocol metadata in gRPC?