docs: update readme

Author: dingyi222666

README.MD

@@ -15,6 +15,10 @@ ChatLuna 核心相关库。
 
   ChatLuna 对话存储相关库，提供相关 API。基于 [minato](https://github.com/cordiverse/minato) 实现与数据库的交互。
 
+- [@chatluna/utils](./packages/utils/README.MD)
+
+  ChatLuna 辅助库，提供一些简单的 API 如 SSE 解析，等待锁等。
+
 - [@chatluna/koishi](./packages/koishi/README.MD)
 
   ChatLuna 运行在 Koishi 上的核心支持库。

packages/core/src/utils/tiktoken.ts

@@ -1,3 +1,9 @@
+import { Request } from '@chatluna/core/service'
+import {
+    ChatLunaError,
+    ChatLunaErrorCode,
+    withResolver
+} from '@chatluna/core/utils'
 import { Context } from '@cordisjs/core'
 import {
     getEncodingNameForModel,
@@ -6,13 +12,7 @@ import {
     TiktokenEncoding,
     TiktokenModel
 } from 'js-tiktoken/lite'
-import { Request } from '@chatluna/core/service'
 import { fetch } from 'undici'
-import {
-    ChatLunaError,
-    ChatLunaErrorCode,
-    withResolver
-} from '@chatluna/core/utils'
 
 globalThis.chatluna_tiktoken_cache = globalThis.chatluna_tiktoken_cache ?? {}
 
@@ -50,12 +50,10 @@ export async function getEncoding(
                 throw e
             })
 
-        const tiktoken = new Tiktoken(
+        cache[encoding] = new Tiktoken(
             tiktokenBPE,
             options?.extendedSpecialTokens
         )
-
-        cache[encoding] = tiktoken
     }
 
     return cache[encoding]