Address requested changes and fix some warnings

MediaBrowser.Controller/SyncPlay/PlaybackRequests/PlayGroupRequest.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Class PlayGroupRequest.
+    /// </summary>
+    public class PlayGroupRequest : IGroupPlaybackRequest
+    {
+        /// <summary>
+        /// Gets the playing queue.
+        /// </summary>
+        /// <value>The playing queue.</value>
+        public List<Guid> PlayingQueue { get; } = new List<Guid>();
+
+        /// <summary>
+        /// Gets or sets the playing item from the queue.
+        /// </summary>
+        /// <value>The playing item.</value>
+        public int PlayingItemPosition { get; set; }
+
+        /// <summary>
+        /// Gets or sets the start position ticks.
+        /// </summary>
+        /// <value>The start position ticks.</value>
+        public long StartPositionTicks { get; set; }
+
+        /// <inheritdoc />
+        public PlaybackRequestType Type { get; } = PlaybackRequestType.Play;
+
+        /// <inheritdoc />
+        public void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(context, state.Type, this, session, cancellationToken);
+        }
+    }
+}