Struct ManagedCOVSubscriptionOptions 

#[non_exhaustive]
pub struct ManagedCOVSubscriptionOptions {
    pub renewal_margin: Duration,
    pub event_channel_capacity: usize,
    pub renewal_gate: Option<Arc<Semaphore>>,
}

Options for a managed finite COV subscription.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

renewal_margin: Duration

How long before the known remaining lifetime the helper should renew.

The helper schedules renewal at time_remaining - renewal_margin, using the requested lifetime until inbound notifications provide a fresher time_remaining value.

event_channel_capacity: usize

Capacity of the renewal event broadcast channel.

Accepted range is 1..=MAX_COV_CHANNEL_CAPACITY.

renewal_gate: Option<Arc<Semaphore>>

A semaphore each renewal takes one permit of before it is sent and holds until its answer, its failure or ManagedCOVSubscription::stop (#1791). An application that limits its own requests to a device (one outstanding at a time, say) passes that limit here, so renewals keep to it too. None (the default) sends renewals ungated.

The first request is not gated: it is sent from the caller’s context, which may already hold a permit for it. A closed semaphore stops gating.

A gated renewal goes only once the permit comes, so whatever holds the gate delays it, by up to that request’s whole time with retries on a device that stops answering. Size renewal_margin to cover that wait as well as the renewal’s own request, or the subscription can lapse first.

Implementations

impl ManagedCOVSubscriptionOptions

pub fn with_renewal_margin(self, margin: Duration) -> Self

Set the renewal margin.

pub fn with_event_channel_capacity(self, capacity: usize) -> Self

Set the renewal event broadcast channel capacity.

pub fn with_renewal_gate(self, gate: Arc<Semaphore>) -> Self

Gate every renewal on a permit of gate (see renewal_gate).

Trait Implementations

impl Clone for ManagedCOVSubscriptionOptions

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 ManagedCOVSubscriptionOptions

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

Formats the value using the given formatter.

impl Default for ManagedCOVSubscriptionOptions

fn default() -> Self

Returns the “default value” for a type.