Fixed: Avoid zero-length array memory allocations

src/NzbDrone.Core/Notifications/Email/EmailSettings.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using FluentValidation;
@@ -35,9 +36,9 @@ namespace NzbDrone.Core.Notifications.Email
             Port = 587;
             Ssl = true;
 
-            To = new string[] { };
-            CC = new string[] { };
-            Bcc = new string[] { };
+            To = Array.Empty<string>();
+            CC = Array.Empty<string>();
+            Bcc = Array.Empty<string>();
         }
 
         [FieldDefinition(0, Label = "Server", HelpText = "Hostname or IP of Email server")]

src/NzbDrone.Core/Notifications/PushBullet/PushBulletSettings.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
@@ -20,8 +21,8 @@ namespace NzbDrone.Core.Notifications.PushBullet
 
         public PushBulletSettings()
         {
-            DeviceIds = new string[] { };
-            ChannelTags = new string[] { };
+            DeviceIds = Array.Empty<string>();
+            ChannelTags = Array.Empty<string>();
         }
 
         [FieldDefinition(0, Label = "Access Token", HelpLink = "https://www.pushbullet.com/#settings/account")]

src/NzbDrone.Core/Notifications/Pushover/PushoverSettings.cs

@@ -23,7 +23,7 @@ namespace NzbDrone.Core.Notifications.Pushover
         public PushoverSettings()
         {
             Priority = 0;
-            Devices = new string[] { };
+            Devices = System.Array.Empty<string>();
         }
 
         //TODO: Get Pushover to change our app name (or create a new app) when we have a new logo

src/NzbDrone.Core/Notifications/SendGrid/SendGridSettings.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
@@ -24,7 +25,7 @@ namespace NzbDrone.Core.Notifications.SendGrid
         public SendGridSettings()
         {
             BaseUrl = "https://api.sendgrid.com/v3/";
-            Recipients = new string[] { };
+            Recipients = Array.Empty<string>();
         }
 
         public string BaseUrl { get; set; }