Struct DownstreamWatch 

pub struct DownstreamWatch { /* private fields */ }

A pull leg’s view of its session’s two downstream frontiers: the paid frontier (FillSession::served_frontier) and the serve demand (FillSession::serve_demand). Read-only and cheap to clone, so a pull on its own runtime holds an owned copy. Minted by FillSession::downstream_watch.

Implementations

impl DownstreamWatch

pub fn served_paid(&self) -> u64

The current paid content frontier.

pub fn serve_demand(&self) -> u64

The nearest content end a starved serve leg awaits, or 0 when none waits.

pub async fn past(&self, observed_paid: u64, observed_demand: u64)

Resolve once served_paid lies past observed_paid or the serve demand differs from observed_demand. Returns at once when either already holds. The demand counts any change: a nearer leg parking lowers it, and the pull must re-decide for that leg as much as for a farther one.

Registers the wakeup BEFORE it re-reads the frontiers. notify_waiters wakes only waiters registered when it fires and stores no permit, so an advance that lands between the caller reading the frontiers and this park would otherwise be lost, and the pull would wait forever (#1673).

Trait Implementations

impl Clone for DownstreamWatch

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DownstreamWatch

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

Formats the value using the given formatter.