The cultmesh-rs document server and the cultnet-rs hub returned the first
failed send_to from maintain, poll_once, poll_resends and receive_event_once,
so one peer whose datagrams cannot be sent failed every poll for every peer.
send_packet now counts a send failure (send_failures() on the document server,
CultNetTransportStats.send_failures on the hub) and returns; only an encode
failure stays an error. The document server treats recv_from ConnectionReset
as Idle, as the socket transport does.
Tests inject the failure at the one send function through a cfg(test) set of
failing peers and prove the other peer is still served.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
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