Open
Description
Basic logging testing are included in #3403 for unary calls.
Test cases are missing for server side streaming, client side streaming and bidi-streaming.
We need more test coverage for logging behaviors on other type of calls beside unary calls.
Also, consider refactor showcase test to not depend on a TestAppender, but rather capture log outputs from console. This will allow logging implementation classes like GrpcLoggingInterceptor to be not public.