public class TimingDecorator : IJob
{
    private readonly IJob _inner;
    private readonly IMetrics _m;
    public TimingDecorator(IJob j, IMetrics m) => (_inner, _m) = (j, m);
    public void Run()
    {
        var sw = Stopwatch.StartNew();
        _inner.Run();
        _m.Record("job_ms", sw.ElapsedMilliseconds);
    }
}