add set_debug method

Author: shijiesheng

cadence/workflow/deterministic_event_loop.py

@@ -37,6 +37,8 @@ def _call_soon(self, callback, args, context) -> Handle:
     def get_debug(self):
         return self._debug
 
+    def set_debug(self, enabled: bool):
+        self._debug = enabled
 
     def run_forever(self):
         """Run until stop() is called."""