Fix: Signature error in plugin example(#11)

Author: haochengxia

docs/src/en/plugin.md

@@ -13,4 +13,15 @@ With user-defined sive python hook functions,
   py::function cache_free_hook;
 ```
 
-We can simulate and determine the cache eviction behavior from the python side.
+We can simulate and determine the cache eviction behavior from the python side.
+
+Here is the signature requirement for these hook functions.
+
+```python
+def cache_init_hook(ccparams: CommonCacheParams) -> CustomizedCacheData: ...
+def cache_hit_hook(data: CustomizedCacheData, req: Request) -> None: ...
+def cache_miss_hook(data: CustomizedCacheData, req: Request) -> None: ...
+def cache_eviction_hook(data: CustomizedCacheData, req: Request) -> int | str: ...
+def cache_remove_hook(data: CustomizedCacheData, obj_id: int | str) ->: ...
+def cache_free_hook(data: CustomizedCacheData) ->: ...
+```

examples/plugin_cache.py

@@ -25,13 +25,13 @@ def cache_remove(self, obj_id):
 def cache_init_hook(common_cache_params: CommonCacheParams):
     return StandaloneLRU()
 
-def cache_hit_hook(cache, obj_id):
-    cache.cache_hit(obj_id)
+def cache_hit_hook(cache, request: Request):
+    cache.cache_hit(request.obj_id)
 
 def cache_miss_hook(cache, request: Request):
     cache.cache_miss(request.obj_id, request.obj_size)
 
-def cache_eviction_hook(cache):
+def cache_eviction_hook(cache, request: Request):
     return cache.cache_eviction()
 
 def cache_remove_hook(cache, obj_id):
@@ -41,7 +41,7 @@ def cache_free_hook(cache):
     cache.cache_data.clear()
 
 plugin_lru_cache = PluginCache(
-    cache_size=1024*1024,
+    cache_size=1024,
     cache_init_hook=cache_init_hook,
     cache_hit_hook=cache_hit_hook,
     cache_miss_hook=cache_miss_hook,
@@ -50,7 +50,7 @@ def cache_free_hook(cache):
     cache_free_hook=cache_free_hook,
     cache_name="CustomizedLRU")
 
-ref_lru_cache = LRU(cache_size=1024*1024)
+ref_lru_cache = LRU(cache_size=1024)
 
 reader = SyntheticReader(
     num_of_req=100000,