nixpkgs/nixos/modules/programs/usbtop.nix

{ config, pkgs, lib, ... }:

let
  cfg = config.programs.usbtop;
in {
  options = {
    programs.usbtop.enable = lib.mkEnableOption "usbtop and required kernel module, to show estimated USB bandwidth";
  };

  config = lib.mkIf cfg.enable {
    environment.systemPackages = with pkgs; [
      usbtop
    ];

    boot.kernelModules = [
      "usbmon"
    ];
  };
}