code: protected function perform(callable $callback, ...$params)
    {
      $result = $callback($this->curl, ...$params);
      if(curl_errno($this->curl) !== CURLE_OK)
        throw new CurlException($this->curl);
  
      if($result === false)
        throw new CurlException("Unable to perform $callback - unknown error.");
  
      return $result;
    }
docs: The curl wrapper itself.
  
  Perfroms an actual call to the cURL library and judges the result.
  
  An exception is thrown if results are found inadequate.
  
  @param callable $callback The name of curl_* function to call.
  @param mixed ...$params Arguments to the call.
  @return mixed The results of the call.