pub fn compose_fallback(
entries: &[Entry],
reason: FallbackReason,
) -> Option<Composed>Expand description
The fallback’s hidden message, composed on srv
(SPEC_CONTEXT_DELIVERY_2026_09_30.md §3.4 step 2, CD2b). Its wire format
is the frontend’s composeReinjectionMessage, unchanged: the
<system-reminder> envelope and REINJECTION_SIGNATURE are how srv’s
digest, the continuation packet and replay recognise a hidden turn. No
part cap: the fallback is one message. None when there is no memory.
A compaction’s running summary is not here: srv’s input handler appends
it (continuity_state::with_state_after_compaction).