code: func NewStructuredLogger(logger *logrus.Logger) func(next http.Handler) http.Handler {
  	return middleware.RequestLogger(&StructuredLogger{logger})
  }
docs: // StructuredLogger is a simple, but powerful implementation of a custom structured
  // logger backed on logrus. I encourage users to copy it, adapt it and make it their
  // own. Also take a look at https://github.com/pressly/lg for a dedicated pkg based
  // on this work, designed for context-based http routers.