// Create a connection to the server
c, err := pop3.DialTLS("pop3.riseup.net:993")
if err != nil {
	log.Fatal(err)
}
defer c.Quit()

// Authenticate with the server
if err = c.Auth("username", "password"); err != nil {
	log.Fatal(err)
}

// Print the UID of all messages in the maildrop
messages, err := c.UidlAll()
if err != nil {
	log.Fatal(err)
}
for _, v := range messages {
	log.Print(v.UID)
}