handle no USR1 signal available on platform

main.py

@@ -158,8 +158,12 @@ def main():
     global can_be_shutdown
     signal.signal(signal.SIGTERM, shutdown_callback)
     signal.signal(signal.SIGINT, shutdown_callback)
+    try:
         signal.signal(signal.SIGUSR1, threads_dump)
 
+    except AttributeError:
+        pass
+
     def help_cli() -> str:
         return """Possible arguments:
     main.py discover