Object
Authenticator for the “PLAIN” SASL mechanism, specified in RFC4616. See Net::IMAP#authenticate.
PLAIN authentication sends the password in cleartext. RFC3501 encourages servers
to disable cleartext authentication until after TLS has been negotiated. RFC8314 recommends TLS
version 1.2 or greater be used for all traffic, and deprecate cleartext
access ASAP. PLAIN can be secured by TLS encryption.