The snapshot fallback sent the caught error's message to the peer, and
errors from getCache or the registry went the same way, so a message the
application or a peer supplied could reach the wire. Its ack fields also
covered the refused request. The snapshot path now refuses per case with
fixed text (the snapshot source failed / the snapshot response is too
large / the snapshot response could not be queued) through refuse(),
which sends unreliable and unordered, so it needs no room in a full
queue, with ack fields that acknowledge nothing, as every runtime's
refusal does. onError keeps the detail.
Tests, with a raw peer that acknowledges nothing: a queue of 8 filled
exactly by an unacknowledged 8-fragment reply, then a refusal that still
arrives and acknowledges nothing; and a getCache failure carrying a
canary, refused with "the snapshot source failed".
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
8b8f8436cc