public class TimeStone
{
private static readonly TimeStoneList TimeStoneList = new TimeStoneList();
private readonly string _stoneName;
private readonly string _category;

public TimeStone(string stoneName)
: this(string.Empty, stoneName)
{
}

public TimeStone(string category, string stoneName)
{
#if DEBUG
_category = category;
_stoneName = stoneName;

DateTime now = DateTime.Now;

TimeStonePair preTimeStonePair = TimeStoneList.FindLast(p => p.First._category == this._category);
TimeSpan timeSpan = preTimeStonePair != null ? now - preTimeStonePair.Second : TimeSpan.Zero;
TimeStoneList.Add(new TimeStonePair(this, now));

Debug.WriteLine(string.Format("TimeStone: {0}${1} Took {2} Ms", _category, _stoneName, Math.Round(timeSpan.TotalMilliseconds)));
#endif
}
}

class TimeStoneList : List<TimeStonePair>
{
}

class TimeStonePair : Pair<TimeStone, DateTime>
{
public TimeStonePair(TimeStone timeStone, DateTime dateTime)
: base(timeStone, dateTime)
{
}
}

public class Pair<TKey, TValue>
{
private TKey _first = default(TKey);

private TValue _second = default(TValue);

public Pair()
{
}

public Pair(TKey first, TValue second)
{
_first = first;
_second = second;
}

public TKey First
{
get { return _first; }
set { _first = value; }
}

public TValue Second
{
get { return _second; }
set { _second = value; }
}

public override bool Equals(object obj)
{
if (obj == null)
return false;
if (obj.GetType() != this.GetType())
return false;
Pair<TKey, TValue> other = obj as Pair<TKey, TValue>;

return _first.Equals(other._first) && _second.Equals(other._second);
}
}