code/Debug/Helper/Http.php
public function getAllHeaders()
    {
        if (!function_exists('getallheaders')) {
            $libRelativePath = 'lib' . DS . 'getallheaders' . DS . 'getallheaders.php';
            $polyfillFilepath = Mage::helper('sheep_debug')->getModuleDirectory() . DS . $libRelativePath;
            require_once($polyfillFilepath);
        }

        return function_exists('getallheaders') ? getallheaders() : array();
    }
public function getAllHeaders()
    {
        if (!function_exists('getallheaders')) {
            $libRelativePath = 'lib' . DS . 'getallheaders' . DS . 'getallheaders.php';
            $polyfillFilepath = Mage::helper('sheep_debug')->getModuleDirectory() . DS . $libRelativePath;
            require_once($polyfillFilepath);
        }

        return function_exists('getallheaders') ? getallheaders() : array();
    }
Wrapper for getallheaders().

This method is not available on CLI
@return array