/// # Example POP3 Session
///
/// S: <wait for connection on TCP port 110>
/// C: <open connection>
/// S: +OK POP3 server ready <1896.697170952@dbc.mtview.ca.us>
/// C: APOP mrose c4c9334bac560ecc979e58001b3e22fb
/// S: +OK mrose's maildrop has 2 messages (320 octets)
/// C: STAT
/// S: +OK 2 320
/// C: LIST
/// S: +OK 2 messages (320 octets)
/// S: 1 120
/// S: 2 200
/// S: .
/// C: RETR 1
/// S: +OK 120 octets
/// S: <the POP3 server sends message 1>
/// S: .
/// C: DELE 1
/// S: +OK message 1 deleted
/// C: RETR 2
/// S: +OK 200 octets
/// S: <the POP3 server sends message 2>
/// S: .
/// C: DELE 2
/// S: +OK message 2 deleted
/// C: QUIT
/// S: +OK dewey POP3 server signing off (maildrop empty)
/// C: <close connection>
/// S: <wait for next connection>
pub use *;