void OnEnterLevel( ActivityMonitorLogData data )
{
Entries.Add( new Entry( data ) );
Writer.WriteLine();
Writer.Write( data.MaskedLevel.ToString() + ": " + data.Text );
if( WriteTags ) Writer.Write( "-[{0}]", data.Tags.ToString() );
if( data.Exception != null ) Writer.Write( "Exception: " + data.Exception.Message );
}