Add field to Replay denoting whether the full replay have been received or not

osu.Game/Replays/Replay.cs

@@ -8,6 +8,12 @@ namespace osu.Game.Replays
 {
     public class Replay
     {
+        /// <summary>
+        /// Whether all frames for this replay have been received.
+        /// If false, gameplay would be paused to wait for further data, for instance.
+        /// </summary>
+        public bool HasReceivedAllFrames = true;
+
         public List<ReplayFrame> Frames = new List<ReplayFrame>();
     }
 }