Provide a simple entry point for ASP.NET recording

[LeeCampbell]

Ideally Web devs should be able to just pull a nuget package and add an attribute to controllers that should be measured.

Potentially an ActionFilterAttibute could be provided in a standalone ASP specific nuget

public class HistogramAttribute : ActionFilterAttribute
{
    private const string StartTimestampKey = "HistogramAttribute.StartTimeStamp";

    public override void OnActionExecuting(ActionExecutingContext context)
    {
        context.HttpContext.Items[StartTimestampKey] = Stopwatch.GetTimestamp();
    }

    public override void OnActionExecuted(ActionExecutedContext context)
    {
        var stopTimestamp = Stopwatch.GetTimestamp();
        var startTimestamp = (long)context.HttpContext.Items[StartTimestampKey];
        var elapsed = stopTimestamp - startTimestamp;
        Log.RecordValue(elapsed);
    }
}

Ideally this would also integrate with tag, recorder and thread safety support.