dechunkstream.php

См. документацию.

<?php
 
namespace Bitrix\Main\Web\Http;
 
class DechunkStream extends Stream
{
    public function __construct($stream, $mode = 'r+')
    {
        parent::__construct($stream, $mode);
 
        stream_filter_append($this->resource, 'dechunk', STREAM_FILTER_WRITE);
    }
}