Randomize LRU cache cycle start pos

src/cache_manager.rs

@@ -20,6 +20,7 @@ use log::{debug, error, info, warn};
 use mime::Mime;
 use openssl::sha::Sha1;
 use parking_lot::{Mutex, RwLock};
+use rand::{thread_rng, Rng};
 use tempfile::TempPath;
 use tokio::{
     fs::{copy, create_dir_all, metadata, read_dir, remove_dir_all, remove_file, rename, DirEntry, File},
@@ -92,7 +93,7 @@ impl CacheManager {
             cache_dir: cache_dir.as_ref().to_path_buf(),
             cache_date: Mutex::new(BTreeSet::new()),
             lru_cache: RwLock::new(vec![]),
-            lru_clear_pos: Mutex::new(0),
+            lru_clear_pos: Mutex::new(thread_rng().gen_range(0..LRU_SIZE)),
             temp_dir: temp_dir.as_ref().to_path_buf(),
             total_size: Arc::new(AtomicU64::new(0)),
             size_limit: AtomicU64::new(u64::MAX),