Improve hands & pulling (#4389)

Content.Shared/Pulling/Events/PullAttemptMessage.cs

@@ -0,0 +1,11 @@
+using Robust.Shared.Physics;
+
+namespace Content.Shared.Physics.Pull
+{
+    public class PullAttemptMessage : PullMessage
+    {
+        public PullAttemptMessage(IPhysBody puller, IPhysBody pulled) : base(puller, pulled) { }
+
+        public bool Cancelled { get; set; }
+    }
+}