static protected function applyDefaultHeaders( $size = NULL, $timestamp = NULL )
	{
		header( "Pragma: public" );
		header( "Expires: -1" );
		header( "Cache-Control: must-revalidate, post-check=0, pre-check=0" );
		if( (int) $size > 0 )
			header( "Content-Length: ".( (int) $size ) );
		$timestamp	= ( (float) $timestamp ) > 1 ? $timestamp : time();
		header( "Last-Modified: ".date( 'r', (float) $timestamp ) );

	}