public virtual void CreatePortMap(Mapping mapping)
        {
            IAsyncResult result = BeginCreatePortMap(mapping, null, null);

            EndCreatePortMap(result);
        }
 public abstract Mapping EndGetSpecificMapping(IAsyncResult result);
 public abstract IPAddress EndGetExternalIP(IAsyncResult result);
 public abstract Mapping[] EndGetAllMappings(IAsyncResult result);
 public abstract void EndDeletePortMap(IAsyncResult result);
 public abstract void EndCreatePortMap(IAsyncResult result);