How to create a service for contents of arbitrary file

[Bone Baboon]

When I use a virtual terminal or Emacs on a virtual terminal using
`emacsclient --tty` I have a blinking cursor.  My preference is to not
have the cursor blink.  I can stop the cursor from blinking by manually
changing the contents of `/sys/class/graphics/fbcon/cursor_blink` to
"0".  I would like to create a service that manages the contents of
`/sys/class/graphics/fbcon/cursor_blink`.

I looked in "Services" as well as the "Defining Services" of the manual
for something similar to `etc-service-type` that allows for the file to
be in any location.

Any suggestions on how to make a service for this?