优化IO问题，使用异步方案进行视频下载等操作。

wechat_ipad/client/tools.py

@@ -1,6 +1,7 @@
 import base64
 import io
 import os
+import aiofiles
 
 import aiohttp
 import pysilk
@@ -234,7 +235,7 @@ class ToolMixin(WechatAPIClientBase):
                 return False
 
     @staticmethod
-    def base64_to_file(base64_str: str, file_name: str, file_path: str) -> bool:
+    async def base64_to_file(base64_str: str, file_name: str, file_path: str) -> bool:
         """将base64字符串转换为文件并保存。
 
         Args:
@@ -256,8 +257,8 @@ class ToolMixin(WechatAPIClientBase):
                 base64_str = base64_str.split(',')[1]
 
             # 解码 base64 并写入文件
-            with open(full_path, 'wb') as f:
-                f.write(base64.b64decode(base64_str))
+            async with aiofiles.open(full_path, 'wb') as f:
+                await f.write(base64.b64decode(base64_str))
 
             return True
 
@@ -265,7 +266,7 @@ class ToolMixin(WechatAPIClientBase):
             return False
 
     @staticmethod
-    def file_to_base64(file_path: str) -> str:
+    async def file_to_base64(file_path: str) -> str:
         """将文件转换为base64字符串。
 
         Args:
@@ -274,8 +275,8 @@ class ToolMixin(WechatAPIClientBase):
         Returns:
             str: base64编码的字符串
         """
-        with open(file_path, 'rb') as f:
-            return base64.b64encode(f.read()).decode()
+        async with aiofiles.open(file_path, 'rb') as f:
+            return base64.b64encode(await f.read()).decode()
 
     @staticmethod
     def base64_to_byte(base64_str: str) -> bytes: