Struct Pool 

pub struct Pool { /* private fields */ }

A shared cache policy and byte budget; cloning shares both.

The pool tracks how many payload bytes are cached across every registered group, plus the mean last-access time of the evictable ones. It never evicts on its own: tracks accrue eviction debt as they write and evict their own oldest groups to pay it. Idle expiration runs during Self::gc. The capacity is therefore a target usage converges toward, not a hard limit: carried debt, capped payments, and the always-protected live edge all let usage transiently exceed it.

Implementations

impl Pool

pub fn new(config: Config) -> Self

Create a pool from an initial policy.

The budget counts frame payload bytes plus a fixed cost per cached group, which is most of what a group carrying one small frame occupies. It is not process RSS, and it is a convergence target rather than a hard limit; leave headroom when sizing it from real memory. The expiry is fixed, while the capacity can later be changed with Self::resize.

pub fn unbounded() -> Self

Create a pool that never evicts. This is the Default.

pub fn capacity(&self) -> Option<u64>

The configured byte target, or None when unbounded.

pub fn used(&self) -> u64

Bytes currently cached across every registered group.

pub fn resize(&self, capacity: impl Into<Option<u64>>)

Change the capacity. None makes the pool unbounded.

Takes effect as tracks write: a shrink leaves the pool over budget, which every subsequent write pays down proportionally. Nothing is reclaimed synchronously.

pub fn expiry(&self) -> Option<Duration>

The wall-clock LRU window, or None when idle content is never reclaimed.

pub fn gc(&self, now: Instant) -> Option<Instant>

Collect idle cache entries and return the next cleanup time.

Call after polling and at the returned deadline, including when idle. Calls before that deadline only advance the pool’s sampled clock. A due pass visits every cached group, dating accesses since the last pass and reclaiming idle groups except each track’s latest. Delayed calls extend retention. Shared pools use the latest supplied instant.

None means both cache policies are disabled. After enabling a capacity with Self::resize, call this again to resume periodic clock sampling.

pub fn downgrade(&self) -> PoolWeak

A handle that reaches this budget without keeping it alive.

Trait Implementations

impl Clone for Pool

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 Pool

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

Formats the value using the given formatter.

impl Default for Pool

fn default() -> Self

Returns the “default value” for a type.