为什么要使用grpclog软件包

I'm looking at the grpc example for go https://grpc.io/docs/tutorials/basic/go.html I’m wondering whats the purpose of grpclog package? the example client/server code uses grpclog.Printf, grpclog.Fatalf. why not just use fmt.Printf & log.Fatalf?

This package forces the logger to only go to verbose level 2 per grpclog

// All logs in transport package only go to verbose level 2.
// All logs in other packages in grpc are logged in spite of the verbosity level.