[Nix-dev] Setting umask for transmission service

[Anders Lundstedt]

I want Transmission downloads created with a umask of 022. However as
described in

https://github.com/NixOS/nixpkgs/commit/da6bc44dd7eb39b68d9b16bc398e64248d7a09c3

this is not possible by setting Transmission's umask settings, since
it is overwritten.

- Any simple workaround?
- What is the reason for overwriting the umask setting?