plugin-go-grpc example keeps creating a new kv-go-grpc sub/process after each run

It seems to commit 0cf1b438bc38d12d59b4361507eb6c1c9c93a470, i.e. https://github.com/hashicorp/go-plugin/blob/master/examples/grpc/main.go#L67 causes a new sub/process for kv-go-grpc being created after each run, no matter the run is successful or not.

Also removing os.Exit(0) at L67 results in "[WARN] plugin: plugin failed to exit gracefully".