pub fn get(&self, key: &K) -> Option<V> {
        let latency = self.metrics.latency[&Method::Get].start();
        let entry = self.cache.as_ref()?.get(key);
        // ^ We intentionally don't report metrics if there's no real cache.

        latency.observe();
        let request_outcome = if entry.is_some() {
            RequestOutcome::Hit
        } else {
            RequestOutcome::Miss
        };
        self.metrics.requests[&request_outcome].inc();

        entry
    }
Gets an entry and pulls it to the front if it exists.
core/lib/state/src/cache/lru_cache.rs