Finish event handlers when disconnecting from an event queue.

This should help prevent timeouts from clients whose requests have
been supplanted.

(imported from commit fdb3a89c4ec02bb23d0fba50ea558d48cb786916)

zerver/middleware.py

@@ -38,6 +38,10 @@ def record_request_restart_data(log_data):
     log_data['bugdown_requests_restarted'] = get_bugdown_requests()
 
 def async_request_restart(request):
+    if "time_restarted" in request._log_data:
+        # Don't destroy data when being called from
+        # finish_current_handler
+        return
     record_request_restart_data(request._log_data)
 
 def record_request_start_data(log_data):