<?php

namespace Symfony\Component\HttpFoundation;

/**
 * HeaderBag is a container for HTTP headers.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 */
class HeaderBag implements \IteratorAggregate, \Countable
{
    /**
     * Returns the headers as a string.
     *
     * @return string The headers
     *
     * @psalm-taint-source input
     */
    public function __toString() {}

    /**
     * @psalm-taint-source input
     * @psalm-mutation-free
     */
    public function get(string $key, string $default = null): ?string {}
}