Setup and control loop devices.
Provides rust interface with similar functionalty to the linux utility losetup.
use loopdev::LoopControl;
let lc = LoopControl::open().unwrap();
let ld = lc.next_free().unwrap();
println!("{}", ld.path().unwrap().display());
ld.attach_file("test.img").unwrap();
// ...
ld.detach().unwrap();