Commands are stored in memory and prevents duplicate jobs

NzbDrone.Common/Messaging/Manager/CommandManagerItem.cs

@@ -0,0 +1,29 @@
+using System;
+
+namespace NzbDrone.Common.Messaging.Manager
+{
+    public class CommandManagerItem
+    {
+        public String Type { get; set; }
+        public ICommand Command { get; set; }
+        public CommandState State { get; set; }
+        
+        public CommandManagerItem()
+        {
+        }
+
+        public CommandManagerItem(ICommand command, CommandState state)
+        {
+            Type = command.GetType().FullName;
+            Command = command;
+            State = state;
+        }
+    }
+
+    public enum CommandState
+    {
+        Running = 0,
+        Completed = 1,
+        Failed = 2
+    }
+}