class Net::IMAP::SASL::ScramAuthenticator

def final_message_with_proof

+client-final-message+.
See {RFC5802 ยง7}[https://www.rfc-editor.org/rfc/rfc5802#section-7] 
def final_message_with_proof
  proof = [client_proof].pack("m0")
  "#{client_final_message_without_proof},p=#{proof}"
end