Struct WaitEpoch 

pub struct WaitEpoch(/* private fields */);

Identifies one specific park of a flow in its mailbox.

Why a timeout needs a token

Cancellation of a ReceiveTimeout deadline is lazy: the timer thread does not remove its entry when a hop wakes the receiver early, it just finds nobody parked when it eventually fires. That reasoning only holds if the flow never parks again before the old deadline — and in a receive loop it always does:

  t=0    ReceiveTimeout(r5, 100ms)  -> park A, timer(100ms) armed
  t=20   hop arrives                -> handoff, park A over, flow runs
  t=30   Receive(r7)                -> park B  (no timeout)
  t=100  timer for park A fires     -> takes park B!
                                       writes Unit into r5, not r7

That is a spurious wake and a write to the previous wait’s register. So Mailbox::park returns the epoch of the park it installed, the timer carries it, and Mailbox::take_parked_at only hands the flow over while that epoch is still current.

There is no public constructor: an epoch can only come from parking, so a timeout cannot present one for a wait that never happened.

Implementations

impl WaitEpoch

pub const fn get(self) -> u64

Raw counter value, for logs and metrics only. Never compare epochs from two different mailboxes: the counter is per-inbox.

Trait Implementations

impl Clone for WaitEpoch

fn clone(&self) -> WaitEpoch

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for WaitEpoch

impl Debug for WaitEpoch

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

Formats the value using the given formatter.

impl Display for WaitEpoch

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

Formats the value using the given formatter.

impl Eq for WaitEpoch

impl Hash for WaitEpoch

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for WaitEpoch

fn eq(&self, other: &WaitEpoch) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for WaitEpoch