rpcserver: dictionary changed size during iteration

[bro]

This error is reported by a YaRSS2 user:

Traceback (most recent call last):
  File "/home/ubuntu/.config/deluge/plugins/YaRSS2-2.1.4-py3.7.egg/yarss2/rssfeed_scheduler.py", line 90, in rssfeed_update_handler_safe                      
    return self.rssfeed_update_handler(rssfeed_key=rssfeed_key, subscription_key=subscription_key)                                                            
  File "/home/ubuntu/.config/deluge/plugins/YaRSS2-2.1.4-py3.7.egg/yarss2/rssfeed_scheduler.py", line 108, in rssfeed_update_handler                          
    subscription_key=subscription_key)
  File "/home/ubuntu/.config/deluge/plugins/YaRSS2-2.1.4-py3.7.egg/yarss2/rssfeed_handling.py", line 372, in fetch_feed_torrents                              
    self.fetch_feed(subscription_data, rssfeed_data, fetch_data)
  File "/home/ubuntu/.config/deluge/plugins/YaRSS2-2.1.4-py3.7.egg/yarss2/rssfeed_handling.py", line 407, in fetch_feed                                       
    self.log.info("Fetching subscription '%s'." % subscription_data["name"])
  File "/home/ubuntu/.config/deluge/plugins/YaRSS2-2.1.4-py3.7.egg/yarss2/util/logging.py", line 42, in info                                                  
    self.handle_gtkui_log(message, gtkui)
  File "/home/ubuntu/.config/deluge/plugins/YaRSS2-2.1.4-py3.7.egg/yarss2/util/logging.py", line 34, in handle_gtkui_log                                      
    self.gtkui_log_message_event(message)
  File "/home/ubuntu/.config/deluge/plugins/YaRSS2-2.1.4-py3.7.egg/yarss2/util/logging.py", line 61, in gtkui_log_message_event                               
    component.get("EventManager").emit(GtkUILogMessageEvent(message))
  File "/usr/lib/python3/dist-packages/deluge/core/eventmanager.py", line 31, in emit                                                                         
    component.get('RPCServer').emit_event(event)
  File "/usr/lib/python3/dist-packages/deluge/core/rpcserver.py", line 541, in emit_event                                                                     
    for session_id, interest in self.factory.interested_events.items():
RuntimeError: dictionary changed size during iteration