backendutil

type TransformBackend struct {
	Backend smtp.Backend

	Transform          func(session *smtp.Session, username string) TransformHandler
	AnonymousTransform func(session *smtp.Session) TransformHandler
}

type TransformHandler interface {
	TransformReset()
	TransformMail(from string) (string, error)
	TransformRcpt(to string) (string, error)
	TransformData(r io.Reader) (io.Reader, error)
}