Use relays when provided

Author: puddly

zigpy_znp/zigbee/application.py

@@ -978,6 +978,9 @@ async def send_packet(self, packet: zigpy.types.ZigbeePacket) -> None:
         association = None
         force_relays = None
 
+        if packet.source_route is not None:
+            force_relays = packet.source_route
+
         tried_assoc_remove = False
         tried_route_discovery = False
         tried_last_good_route = False