Probleme with attachement file in watcher kibana


I have a problem with watcher in elasticsearch, in fact I created a watcher that allows to send a mail with a pdf file ( the pdf file is a dashboard on kibana )
"reporting": {
"url": "http://kibana:5601/api/reporting/generate/...

the problem is that the file sent is not complete (there are dashboards not loaded..)

How can I make sure that the file is sent only when all the dashboards are complete.