/**
  * send message and return message array
  *
  * @param string $folderName
  * @param array $addtionalHeaders
  * @return array
  */
 protected function _sendMessage($folderName = 'INBOX', $addtionalHeaders = array())
 {
     $messageToSend = $this->_getMessageData();
     $messageToSend['headers'] = array_merge($messageToSend['headers'], $addtionalHeaders);
     $returned = $this->_json->saveMessage($messageToSend);
     $this->_foldersToClear = array('INBOX', $this->_account->sent_folder);
     $result = $this->_getMessages($folderName);
     $message = $this->_getMessageFromSearchResult($result, $messageToSend['subject']);
     $this->assertTrue(!empty($message), 'Sent message not found.');
     return $message;
 }