send_email_2.java

@Value
@Accessors(fluent = true)
public class EmailAddress {
    private final String value;
}

@Value
@Accessors(fluent = true)
public class Payload {
    private final String message;
}

public class EmailSender {
    public boolean send(EmailAddress emailAddress, Payload payload) {
        return doSend(emailAddress.value(), payload.message());
    }
}