/**
  * @param $file
  * @return array
  */
 protected function prepareRequestHeaders($file)
 {
     $headers = array();
     $headers['User-Agent'] = 'smsapi-php-client';
     $headers['Accept'] = '';
     if ($this->isFileValid($file)) {
         $headers['Content-Type'] = 'multipart/form-data; boundary=' . $this->boundary;
     } else {
         $headers['Content-Type'] = 'application/x-www-form-urlencoded';
     }
     if ($this->basicAuthentication) {
         $headers['Authorization'] = 'Basic ' . base64_encode($this->basicAuthentication->getUsername() . ':' . $this->basicAuthentication->getPassword());
     }
     return $headers;
 }
 /**
  * @return string
  */
 protected function paramsLoginToQuery()
 {
     return "username="******"&password=" . $this->client->getPassword();
 }