code: 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();
      }
docs: Wrapper for getallheaders().
  
  This method is not available on CLI
  @return array