add tracing to interop server

tonic-interop/src/bin/server.rs

@@ -12,7 +12,11 @@ struct Opts {
 async fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
     let matches = Opts::from_args();
 
+    // let sub = tracing_fmt::FmtSubscriber::builder().finish();
+    // tracing::subscriber::set_global_default(sub).unwrap();
+    // let _ = tracing_log::LogTracer::init();
     pretty_env_logger::init();
+
     let addr = "127.0.0.1:10000".parse().unwrap();
 
     let test_service = server::create();