http\Encoding\Stream

defl.php

<?php

use http\Encoding\Stream;

$stream = new Stream\Deflate(
    Stream::FLUSH_SYNC | 
    Stream\Deflate::TYPE_RAW );

$encoded = "";
$threshold = 500;

while (strlen($encoded) < $threshold) {
    $encoded .= $stream->update(file_get_contents(__FILE__));
}
$encoded .= $stream->finish();

var_dump(strlen($encoded), strlen(zlib_decode($encoded)));