Enum BackpressurePolicy 

pub enum BackpressurePolicy {
    Drop,
    SpinThenBlock,
    Block,
}

Backpressure policy to apply when routing to consumers.

Contract

• Backpressure policies only affect the router loop (this crate). Producers and consumers are still nonblocking and may observe drops depending on mode and policy.
• In v1, only [RouterMode::WorkQueue] can apply backpressure without changing the ABI layout. [RouterMode::Broadcast] remains best-effort and uses drop-on-full semantics.

Notes

• BackpressurePolicy::SpinThenBlock is a CPU-side wait strategy; it does not use wake sections.
• BackpressurePolicy::Block uses optional v1 wake sections when available; if wake-backed waits fail at runtime, the loop falls back to the provided [WaitStrategy].

Variants

Drop

Drop when a destination queue is full.

SpinThenBlock

When routing in RouterMode::WorkQueue, avoid dequeuing a message if all consumer queues are full; instead, apply the configured wait strategy until at least one consumer has capacity.

Notes:

• This is a v1 best-effort policy; it does not use wake sections.
• In RouterMode::Broadcast, this policy behaves like Drop (broadcast cannot be made “all-or-nothing” without a different layout).

Block

Use the optional v1 wake sections (INDEXBUS_CAP_SUPPORTS_BLOCKING) to block the router thread when idle or when all consumers are full.

Notes:

• Implemented only for RouterMode::WorkQueue.
• If wake sections are unavailable, this falls back to the configured wait strategy.

Trait Implementations

impl Clone for BackpressurePolicy

fn clone(&self) -> BackpressurePolicy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BackpressurePolicy

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

Formats the value using the given formatter.

impl PartialEq for BackpressurePolicy

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for BackpressurePolicy

impl Eq for BackpressurePolicy

impl StructuralPartialEq for BackpressurePolicy