src/Bundle/Common/Bag/ServerBag.php
public function fetch(string $key, $default = null)
    {
        if (isset($_SERVER[$key])) {
            return $_SERVER[$key];
        } else {
            $key = 'HTTP_' . $key;
            return $_SERVER[$key] ?? $default;
        }
    }
public function fetch(string $key, $default = null)
    {
        if (isset($_SERVER[$key])) {
            return $_SERVER[$key];
        } else {
            $key = 'HTTP_' . $key;
            return $_SERVER[$key] ?? $default;
        }
    }
Returns a SERVER parameter by name.

@param string $key
@param mixed|null $default The default value if the parameter key does not exist
@return mixed|null