The second case here provides separate client and server instances.
Running this example requires starting the server and client separately.
start server
The server provides some flags for you.
If you run it without flags, it serves on https://localhost:6121/ and
uses certificated files under server/testdata.
start client
Use args to specify the destination. If no args, the client make a request to https://localhost:6121/ by default.
# under http3-demo/server
go run main.go https://localhost:8080