$smtp->mail(address[, options])
$smtp->send(address)
send_or_mail(address)
send_and_mail(address)
Takes the sender's address and sends the appropriate command (MAIL, SEND,
SOML, or SAML) to the server to initiate the message-sending process.
mail can take some ESMTP options, passed as key/value pairs.
See the Net::SMTP documentation for the details.
