Struct RetentionPolicy 

pub struct RetentionPolicy<K, V>
where
    K: Clone + Eq + Hash + Send + Sync + 'static,
    V: Clone + Send + Sync + 'static,
{
    pub score: Arc<dyn Fn(&K, &V) -> f64 + Send + Sync>,
    pub archive_threshold: Option<f64>,
    pub max_size: Option<usize>,
    pub on_archive: Option<Arc<dyn Fn(&K, &V, f64) + Send + Sync>>,
}

Score-based retention policy for ReactiveMap.

After every mutation, entries are scored and those below archive_threshold (or exceeding max_size by ascending score) are archived (deleted). Mutually exclusive with top-level max_size (LRU).

Fields

score: Arc<dyn Fn(&K, &V) -> f64 + Send + Sync>

Score function — higher is kept.

archive_threshold: Option<f64>

Entries scoring below this threshold are archived.

max_size: Option<usize>

Maximum number of live entries. Lowest-scored entries archived first.

on_archive: Option<Arc<dyn Fn(&K, &V, f64) + Send + Sync>>

Called for each archived entry.