Setting response header / Hx-Trigger

[muhis]

Great stuff on Fasthtml, I have been enjoying it a lot.
I am trying to understand how to set response header, mainly, I am trying to set Hx-Trigger. The application I have is a modal that has a form. When the form is submitted and handled successfully, I would like to do two actions:

1. Update UI with the newly created element.
2. modal.close()
   The first is easy. The second one is more difficult. I did research and found that the best way is to trigger a custom event via the aforementioned hx-trigger. I searched a lot and I can't find how to set such trigger with fasthtml.
   This is a video of what I am trying to achieve:

htmx_modals.mp4

This video is from an article on how to do this in Django:
https://github.com/spookylukey/django-htmx-patterns/blob/master/modals.rst