Struct TrialGuard 

pub struct TrialGuard<'b> { /* private fields */ }

RAII guard for one admitted pull-through attempt.

Returned inside Admission::Proceed by OriginBreaker::acquire. It exists to make the HALF-OPEN trial budget cancellation-safe: a half-open trial reserves a half_open_in_flight slot at admission, and that slot must be returned even if the surrounding async fetch is cancelled (client disconnect / timeout) before its outcome is known.

Resolution happens exactly one of two ways:

• TrialGuard::record commits the outcome — driving the CLOSED→OPEN, HALF-OPEN→CLOSED, and HALF-OPEN→OPEN transitions — and defuses the guard so Drop does nothing.
• The guard is dropped without record (the future was cancelled): Drop releases the reserved HALF-OPEN slot (a no-op for a CLOSED admission, which reserves no slot) without recording any state transition. The breaker neither closes nor re-opens on a cancelled trial — it simply reclaims the budget so a later trial is admitted.

The guard borrows the breaker, so it cannot outlive it; the engine holds each breaker for the whole pull-through call, which strictly outlives the guard.

Implementations

impl TrialGuard<'_>

pub fn record(self, outcome: OriginOutcome)

Commit the outcome of the admitted attempt and defuse the guard.

Drives the breaker’s state transitions (the private OriginBreaker::record_committed) and clears owns_slot so the guard’s Drop does not also release the HALF-OPEN slot — record already accounts for the slot it resolves. For an inert guard (disabled policy) this is a no-op.

Trait Implementations

impl<'b> Debug for TrialGuard<'b>

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

Formats the value using the given formatter.

impl Drop for TrialGuard<'_>

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.