class Net::IMAP::SASL::ScramAuthenticator

def client_first_message_bare

+client-first-message-bare+.
See {RFC5802 ยง7}[https://www.rfc-editor.org/rfc/rfc5802#section-7] 
def client_first_message_bare
  @client_first_message_bare ||=
    format_message(n: gs2_saslname_encode(SASL.saslprep(username)),
                   r: cnonce)
end