Enum DeadlineOutcomeInto 

pub enum DeadlineOutcomeInto {
    Reply(usize),
    SendFailed,
    PeerDied,
    QueueFull,
    Timeout,
}

Outcome of ServiceContext::request_with_reply_deadline_outcome_into - the buffer-writing twin of DeadlineOutcome.

It exists because the _into form collapsed all four outcomes into Option<usize>, and the two that matter are OPPOSITES. SendFailed means the request never left, so nothing can arrive late and retrying after a reacquire is safe. Timeout means it DID leave, so a late reply is still coming and re-sending desyncs the protocol - every later reply is matched to the wrong request. A caller handed None cannot tell those apart, so it must either never retry (and stay broken after a peer restarts) or always retry (and desync). fs had the first of those.

Variants

Reply(usize)

A reply arrived; the payload is in the caller’s buffer, this many bytes of it.

SendFailed

The send never left: the peer’s cap is stale or its name does not currently resolve. Nothing is in flight. Reacquire by name and retry ONCE - this is the only safe retry.

PeerDied

The request WAS delivered, and the peer died holding it (ReplyDead, 8.6), so the work may have been done. Re-send only an operation that is safe to repeat (a block read, a rewrite of the same sector). It was folded into SendFailed until 2026-10-10 (backlog/fixed/80 S3); gs::call has kept the two apart all along, as Error::PeerDied against Error::Unreachable.

QueueFull

The peer’s queue was full. The request did not leave either, but the peer is alive and busy.

Timeout

The request was delivered and no reply came in time. Do NOT re-send.

Trait Implementations

impl Debug for DeadlineOutcomeInto

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.