Optionalid: any
the stream_id
Optionalsubject: any
the subject
Optionalverified: any
the Add Subject request's verified (true unless
false)
Optionaloptions: any
criticalMembers, the transmitter's
critical_subject_members
{ ok, errors, added, subject }; added is false when it was
already there
Adds a subject to a stream, after validating it.