(buffer, character-string, read) Buffer with SASL
gss_OID * mech_type
(OID, modify, optional) Actual mechanism used. The OID
returned via this parameter will be a pointer to static storage
that should be treated as read-only; In particular the
application should not attempt to free it. Specify NULL if not
Output GSS-API mechanism OID of mechanism associated with given
`GSS_S_COMPLETE`: Successful completion.
`GSS_S_BAD_MECH`: There is no GSS-API mechanism known as sasl_mech_name.