Description
Is your feature suggestion related to a problem? Please describe.
I have a use-case where I need to draw additional lines, background and/or labels to visually separate time slots. I also think it is likely that my app will need to add more customized visual elements to the calendar in the future.
Describe the solution you'd like
A way to define additional custom drawers that can add visual elements to the background grid (or on top of any layer) would help.
Describe alternatives you've considered
Obviously forking the project and adding my additional drawing code there would work, but other people may have similar use-cases, and I'd have to rebase every time I want to update the library.
Additional context
I have a change and will submit a PR