Enum WaitStrategy 

pub enum WaitStrategy {
    BusySpin,
    YieldSpin,
    Park,
    Adaptive {
        spin_iters: u32,
        yield_iters: u32,
    },
}

Strategy for blocking recv() and SubscriberGroup::recv().

Controls how the consumer thread waits when no message is available. Choose based on your latency vs CPU usage requirements:

Strategy	Latency	CPU usage	Best for
BusySpin	Lowest (~0 ns wakeup)	100% core	HFT, dedicated cores
YieldSpin	Low (~1-5 us wakeup)	High	Shared cores, SMT
Park	Medium (~10-50 us wakeup)	Near zero	Background consumers
Adaptive	Auto-scaling	Varies	General purpose

Variants

BusySpin

Pure busy-spin with no PAUSE instruction. Minimum wakeup latency but consumes 100% of one CPU core. Use on dedicated, pinned cores.

YieldSpin

Spin with thread::yield_now() between iterations. Yields the OS time slice to other threads on the same core. Good for SMT.

Park

thread::park() / unpark() based waiting. Near-zero CPU usage when idle but higher wakeup latency (~10-50 us depending on OS).

Adaptive

Three-phase escalation: busy-spin for spin_iters iterations, then yield for yield_iters, then park. Balances latency and CPU.

On no_std (without the std feature), the yield and park phases fall back to core::hint::spin_loop().

Fields

spin_iters: u32

Number of bare-spin iterations before escalating.

yield_iters: u32

Number of yield iterations before parking (or PAUSE-spinning on no_std).

Trait Implementations

impl Clone for WaitStrategy

fn clone(&self) -> WaitStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WaitStrategy

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

Formats the value using the given formatter.

impl Default for WaitStrategy

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for WaitStrategy

fn eq(&self, other: &WaitStrategy) -> 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 WaitStrategy

impl Eq for WaitStrategy

impl StructuralPartialEq for WaitStrategy