in handler.go [24:34]
func (a *App) Handler(w http.ResponseWriter, r *http.Request) {
a.log.Log(logging.Entry{
Severity: logging.Info,
HTTPRequest: &logging.HTTPRequest{
Request: r,
},
Labels: map[string]string{"arbitraryField": "custom entry"},
Payload: "Structured logging example.",
})
fmt.Fprintf(w, "Hello World!\n")
}