request_force_close: add 1s delay before closing the tranport,

so that the remote task does not get cancelled.

electrum/lnworker.py

@@ -2268,15 +2268,20 @@ class LNWallet(LNWorker):
             peer_addr = LNPeerAddr(host, port, node_id)
             transport = LNTransport(privkey, peer_addr, proxy=self.network.proxy)
             peer = Peer(self, node_id, transport, is_channel_backup=True)
+            async def trigger_force_close_and_wait():
+                # wait before closing the transport, so that
+                # remote has time to process the message.
+                await peer.trigger_force_close(channel_id)
+                await asyncio.sleep(1)
+                peer.transport.close()
             try:
                 async with OldTaskGroup(wait=any) as group:
                     await group.spawn(peer._message_loop())
-                    await group.spawn(peer.trigger_force_close(channel_id))
+                    await group.spawn(trigger_force_close_and_wait())
                 return
             except Exception as e:
                 self.logger.info(f'failed to connect {host} {e}')
                 continue
-            # TODO close/cleanup the transport
         else:
             raise Exception('failed to connect')