Added reporting the package download speed along with the download time as its own metric. (#413)

Author: agr

src/Validation.Common.Job/CommonTelemetryService.cs

@@ -10,8 +10,10 @@ namespace NuGet.Jobs.Validation
     public class CommonTelemetryService : ICommonTelemetryService
     {
         private const string PackageDownloadedSeconds = "PackageDownloadedSeconds";
+        private const string PackageDownloadSpeed = "PackageDownloadSpeedBytesPerSec";
         private const string PackageUri = "PackageUri";
         private const string PackageSize = "PackageSize";
+        private const double DefaultDownloadSpeed = 1;
 
         private readonly ITelemetryClient _telemetryClient;
 
@@ -35,6 +37,14 @@ public void TrackPackageDownloaded(Uri packageUri, TimeSpan duration, long size)
                     { PackageUri, absoluteUri },
                     { PackageSize, size.ToString() },
                 });
+            _telemetryClient.TrackMetric(
+                PackageDownloadSpeed,
+                duration.TotalSeconds > 0 ? size / duration.TotalSeconds : DefaultDownloadSpeed,
+                new Dictionary<string, string>
+                {
+                    { PackageUri, absoluteUri },
+                    { PackageSize, size.ToString() },
+                });
         }
     }
 }