Fixed: Avoid zero-length array memory allocations

src/NzbDrone.Core/Download/Clients/Deluge/DelugeProxy.cs

@@ -349,7 +349,7 @@ namespace NzbDrone.Core.Download.Clients.Deluge
         {
             if (result.Torrents == null)
             {
-                return new DelugeTorrent[0];
+                return Array.Empty<DelugeTorrent>();
             }
 
             return result.Torrents.Values.ToArray();

src/NzbDrone.Core/Download/Clients/Hadouken/HadoukenProxy.cs

@@ -106,7 +106,7 @@ namespace NzbDrone.Core.Download.Clients.Hadouken
         {
             if (torrentsRaw == null)
             {
-                return new HadoukenTorrent[0];
+                return Array.Empty<HadoukenTorrent>();
             }
 
             var torrents = new List<HadoukenTorrent>();

src/NzbDrone.Core/Download/TrackedDownloads/TrackedDownload.cs

@@ -17,7 +17,7 @@ namespace NzbDrone.Core.Download.TrackedDownloads
 
         public TrackedDownload()
         {
-            StatusMessages = new TrackedDownloadStatusMessage[] { };
+            StatusMessages = System.Array.Empty<TrackedDownloadStatusMessage>();
         }
 
         public void Warn(string message, params object[] args)