use std::collections::HashMap;

/// Size of the LRU cache.
const CACHE_SIZE: usize = 1024;

    loaded: Mutex<lru_cache::LruCache<u64, Box<[u8; crate::tag::BLOCK_SIZE]>>>,

    loaded: Mutex<HashMap<u64, Box<[u8; crate::tag::BLOCK_SIZE]>>>,

            loaded: Mutex::new(lru_cache::LruCache::new(CACHE_SIZE)),

            loaded: Mutex::new(HashMap::new()),

    }
    /// Clear the cache, freeing memory.
    pub fn clear(&mut self) {
        // This function is only safe because it takes a mutable
        // borrow, and all references returned by the methods on
        // `TagTxn` return immutable borrows of `self`.
        self.loaded.lock().unwrap().clear()