diff --git a/ppadb/sync_async/__init__.py b/ppadb/sync_async/__init__.py
index 4f65540..7ceff64 100644
--- a/ppadb/sync_async/__init__.py
+++ b/ppadb/sync_async/__init__.py
@@ -63,7 +63,7 @@ async def push(self, src, dest, mode, progress=None):
                     progress(src, total_size, sent_size)
 
         # DONE
-        await self._send_length(Protocol.DONE, timestamp)
+        await self._send_length(Protocol.DONE, int(timestamp))
         await self.connection._check_status()
 
     async def pull(self, src, dest):