use flate2::write::GzEncoder;
eprintln!("Usage: `source` `target`");
let mut input = BufReader::new(File::open(args().nth(1).unwrap()).unwrap());
let output = File::create(args().nth(2).unwrap()).unwrap();
let mut encoder = GzEncoder::new(output, flate2::Compression::default());
let start = Instant::now();
copy(&mut input, &mut encoder).unwrap();
let output = encoder.finish().unwrap();
input.get_ref().metadata().unwrap().len()
println!("Target len: {:?}", output.metadata().unwrap().len());
println!("Elapsed: {:?}", start.elapsed());