/**
 * Storage.php
 */

class Storage
{
    
    private $data;

    public function __get($key)
    {
        return $this->data[$key] ?? null;
    }

    public function __set($key, $value)
    {
        $this->data[$key] = $value;
    }

}

/**
 * Inside Some\Class\With\CallbackStackProcessing::process()
 */

$storage = new Storage;
$result  = $this->data;

foreach ($this->processors as $processor)
{
    $result = Closure::bind($processor, $storage)($result);
}

return $result;

/**
 * Callbacks in Some\Class\With\CallbackStackProcessing::$processors
 */

[
    function ($data) {
        $this->counter = count($data);
        
        return $data;
    },
    function ($data) {
        return array_map($data, function ($item) {
            return (int) $data;
        });
    },
    function ($data) {
        if ($data[0] < 100) return false;

        return $data;
    },
    function ($data) {
        return [
            'before' => $this->counter,
            'items'  => $data,
            'after'  => count($data),
        ];
    },
]