fix megatron weights sync

src/twinkle/model/megatron/megatron.py

@@ -1645,36 +1645,27 @@ def weight_generator():
                 pass
             return
 
-        import queue
-        buf: queue.Queue = queue.Queue(maxsize=4)
-        error: list = []
+        async def _send():
+            await engine.send_weights(weight_generator())
 
-        def _send():
+        result_container = {'error': None}
 
-            def _iter():
-                while (item := buf.get()) is not None:
-                    yield item
-
-            loop = asyncio.new_event_loop()
+        def _run():
             try:
-                loop.run_until_complete(engine.send_weights(_iter()))
-            except Exception as exc:
-                error.append(exc)
-            finally:
-                loop.close()
-
-        sender = threading.Thread(target=_send, name='ce-broadcast', daemon=True)
-        sender.start()
-        try:
-            for name, tensor in weight_generator():
-                buf.put((name, tensor.clone()))
-                if error:
-                    break
-        finally:
-            buf.put(None)  # sentinel
-        sender.join()
-        if error:
-            raise error[0]
+                loop = asyncio.new_event_loop()
+                asyncio.set_event_loop(loop)
+                try:
+                    loop.run_until_complete(_send())
+                finally:
+                    loop.close()
+            except Exception as e:
+                result_container['error'] = e
+
+        thread = threading.Thread(target=_run)
+        thread.start()
+        thread.join()
+        if result_container['error'] is not None:
+            raise result_container['error']
 
     @remote_function(collect='first')
     def get_peft_config_dict(self, adapter_name: str = None) -> dict: