Application insights extension to track an event and record the duration of it as a metric associated to the Event

TrackEventOperation.cs

    public static class TelemetryClientExtensions
    {
        public static IOperationHolder<TrackEventOperation> StartEventOperation(this TelemetryClient client, string eventName)
        {
            return new TrackEventOperationHolder(eventName, client);
        }
    }

    public class TrackEventOperationHolder : IOperationHolder<TrackEventOperation>
    {
        private bool _disposed;
        private Stopwatch _stopwatch;
        
        private readonly TelemetryClient _client;

        public TrackEventOperation Telemetry { get; private set; }

        public TrackEventOperationHolder(string eventName, TelemetryClient client)
        {
            _client = client;

            this.Telemetry = new TrackEventOperation(eventName);

            _stopwatch = Stopwatch.StartNew();
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!_disposed)
            {
                if (disposing)
                {
                    try
                    {
                        _stopwatch.Stop();
                        _client.TrackEvent(this.Telemetry.EventName, metrics: new Dictionary<string, double> { { "processingTime", _stopwatch.ElapsedMilliseconds } });
                    }
                    catch (Exception ex)
                    {
                        Trace.TraceError(ex.ToString());
                    }
                }
                _disposed = true;
            }
        }
    }

    public class TrackEventOperation
    {
        public string EventName { get; set; }

        public TrackEventOperation(string eventName)
        {
            this.EventName = eventName;
        }
    }