Struct Engine 

pub(crate) struct Engine<'a> {
    pub(crate) queue: Option<Queue<'a>>,
    pub(crate) closer: &'a SessionCloser,
}

Everything execute may mutate.

Fields

queue: Option<Queue<'a>>

The stream’s queue, or None at the datagram site.

Datagrams are per-connection and unordered by definition, so they have no queue — and Action::Delay / Action::Hold are refused there, so nothing can need one. None is not a degraded mode; it is the datagram site’s shape.

closer: &'a SessionCloser

Where Action::CloseSession is recorded.

Implementations

impl Engine<'_>

fn queue_is_busy(&self) -> bool

Whether a unit written now would overtake something already waiting — or would escape the pacer.

The second term is the whole of the release wiring’s reach into this module. Plan::WriteNow hands bytes straight to the transport, which is correct and cheap on an unshaped stream and is exactly the path a token bucket cannot see: PendingQueue::pop_next_due is the release seam, and a unit that never enters the queue never reaches it. So a shaped queue is always busy, and every unit on a shaped stream is released rather than written.

Nothing else in this module knows a class, a bucket or a discipline. The queue tags what it is handed from the class the pipe loop last resolved, so push_unit stays the one place a push and its ledger entry happen together.

Trait Implementations

impl<'a> Debug for Engine<'a>

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

Formats the value using the given formatter.