code: protected function getMostRecentUnreadEmail()
    {
      if(empty($this->unreadInbox))
      {
        $this->fail('Unread Inbox is Empty');
      }
  
      $email = array_shift($this->unreadInbox);
      $content = $this->getFullEmail($email->id);
      $content->Headers = $this->getHeaders($email->id)->headers;
      return $content;
    }
docs: Get Most Recent Unread Email
  
  Pops the most recent unread email, fails if the inbox is empty
  
  @return mixed Returns a JSON encoded Email