Rewrite syncplay using a state design pattern

MediaBrowser.Model/SyncPlay/SyncPlayBroadcastType.cs

@@ -0,0 +1,28 @@
+namespace MediaBrowser.Model.SyncPlay
+{
+    /// <summary>
+    /// Used to filter the sessions of a group.
+    /// </summary>
+    public enum SyncPlayBroadcastType
+    {
+        /// <summary>
+        /// All sessions will receive the message.
+        /// </summary>
+        AllGroup = 0,
+
+        /// <summary>
+        /// Only the specified session will receive the message.
+        /// </summary>
+        CurrentSession = 1,
+
+        /// <summary>
+        /// All sessions, except the current one, will receive the message.
+        /// </summary>
+        AllExceptCurrentSession = 2,
+
+        /// <summary>
+        /// Only sessions that are not buffering will receive the message.
+        /// </summary>
+        AllReady = 3
+    }
+}