code: protected function processHeaders($headers)
      {
          $out = array();
  
          $headers = explode("\r\n", trim($headers));
  
          foreach ($headers as $header) {
              if (strpos($header, ':') !== false) {
                  $tmp = explode(':', $header);
  
                  $out[reset($tmp)] = end($tmp);
              } else {
                  if (!isset($out['http-code'])) {
                      $out['http-code'] = $header;
                  }
              }
          }
  
          unset($headers, $header, $tmp);
  
          return $out;
      }
docs: Returns response headers as array
  
  This can be useful to avoid extra requests for rate-limit info
  x-rate-limit-limit      (max request per period)
  x-rate-limit-remaining  (remaining this period)
  x-rate-limit-reset      (start of next period, UTC timestamp)
  
  @param array $headers Headers string
  @return array  Headers array