refactor: derice traits for cache hint

Signed-off-by: MrCroxx <[email protected]>

foyer-memory/src/record.rs

@@ -15,6 +15,7 @@
 use std::sync::atomic::{AtomicIsize, AtomicU64, Ordering};
 
 use bitflags::bitflags;
+use serde::{Deserialize, Serialize};
 
 use crate::{eviction::Eviction, slab::Token};
 
@@ -27,6 +28,7 @@ use crate::{eviction::Eviction, slab::Token};
 /// it to a proper one.
 ///
 /// For more details, please refer to the document of each enum options.
+#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
 pub enum CacheHint {
     /// The default hint shared by all cache eviction algorithms.
     Normal,