ssl property
Connect to the smtp server over a secure ssl connection.
Setting this option to false does NOT mean, that mails will be sent over
unencrypted connections!
SSL for smtp servers is uncommon!
Usually this library will connect to the server over an insecure
connection first and use the smtp command starttls to upgrade the
connection to a secure one. If the server doesn't support
starttls we will abort if allowInsecure is false.
Implementation
final bool ssl;