module Net::IMAP::SASL::GS2Header

"+F,+".
flag. A class for a nonstandard GSSAPI mechanism should prefix with
the SASL mechanisms using GS2 are "standard", we don't include that
indicate that the GSS mechanism is not "standard", but since all of
Note: the actual GS2 header includes an optional flag to
>>>

+gs2-header+, which prefixes the #initial_client_response.
The {RFC5801 §4}[https://www.rfc-editor.org/rfc/rfc5801#section-4]

def gs2_header
  "#{gs2_cb_flag},#{gs2_authzid},"
end