constructor_injection

type Dog struct{}

type Mailer struct {
	Host     string
	Port     string
	Username string
	Password string
}

type MailerInterface interface {
	Send(to string, body string) error
	Receive(address string) (string, error)
}

type Sender interface {
	Send(to string, body string) error
}

type Talker interface {
	Speak() string
	Shout() string
}

type WelcomeSender struct {
	// contains filtered or unexported fields
}

type WelcomeSenderV2 struct {
	// contains filtered or unexported fields
}