Enum OverflowPolicy 

pub enum OverflowPolicy {
    Block(Duration),
    DropNewest,
}

What a Queue does when its channel is full.

Variants

Block(Duration)

Block the pushing thread until there’s room, up to Duration — the right choice for offline/file processing, where correctness matters more than staying caught up. Use Duration::MAX (what OverflowPolicy::default does) for what’s practically an unbounded wait — [Sender::send_timeout] with that duration isn’t ever going to time out in a real program.

A finite Duration is the escape hatch against the one thing an actually-unbounded wait can’t recover from: whatever’s downstream not just falling behind (ordinary backpressure, which resolves on its own as the worker keeps draining) but genuinely stuck — a Sink::consume call somewhere in the chain that never returns. An unbounded wait here would then also wedge whoever’s pushing into this Queue, and transitively every Queue upstream of that, since each one’s worker can’t get back to its own control_rx until its current downstream.consume() call returns (see Queue::control’s own docs on why control is only ever checked between buffers, not able to preempt one already in flight). Timing out bounds that: it’s what lets a Stop sent to an upstream Queue eventually reach it instead of waiting forever. Doesn’t help if the stall is inside a raw (non-Queue) Sink’s own consume() call directly — nothing here retries or times out that call itself, only the channel send. On timeout, returns QueueError::SendTimedOut rather than losing the buffer silently — unlike OverflowPolicy::DropNewest, this isn’t an expected, routine condition.

This timeout applies to ordinary data buffers only. Queue sends MediaBuffer::Eos with an unbounded send under every policy so a natural end-of-stream marker is never discarded; if downstream has stopped consuming entirely, an EOS push can therefore still block.

DropNewest

Drop the incoming buffer instead of blocking, and post BusEvent::Dropped. Never stalls the upstream thread — the right choice for live sources, where falling behind is worse than losing a frame.

Trait Implementations

impl Clone for OverflowPolicy

fn clone(&self) -> OverflowPolicy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for OverflowPolicy

impl Debug for OverflowPolicy

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

Formats the value using the given formatter.

impl Default for OverflowPolicy

fn default() -> Self

Returns the “default value” for a type.

impl Eq for OverflowPolicy

impl PartialEq for OverflowPolicy

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for OverflowPolicy