type HostOption struct {
// The name of the host Name string// Dkim PEM key file DkimKey string// The text DNS selector DkimSelector string// The certificate and key for the TLS connexion Cert, Key string
}
type Option struct {
// The log output Out io.Writer// Listen address Addrs []string// All the hosts Hosts []HostOption AuthTest AuthTest// the file that contain login and password. Used if AuthTest is nil AuthFile string
}