Handler::__construct

public function __construct($stream, $mode = 'r+')
{
	parent::__construct($stream, $mode);

	// ZLIB or GZIP: use window=$W+32 for automatic header detection, so that both the formats can be recognized and decompressed; window=15+32=47 is the safer choice.
	stream_filter_append($this->resource, 'zlib.inflate', STREAM_FILTER_WRITE, ['window' => 47]);
}