Function archive_transcript 

pub fn archive_transcript(
    memory_dir: &Path,
    adapter: &dyn Transcript,
    transcript: &TranscriptRef,
    archived: &HashSet<String>,
) -> Result<Option<ArchiveResult>, RecallError>

Read one transcript and archive it.

Ok(None) means the transcript turned out to be already archived under the id its contents report — the second half of the double-ingest check.