code: protected function getFullEmail($id)
    {
      try
      {
        $response = $this->sendRequest('GET', "/api/v1/inboxes/{$this->config['inbox_id']}/messages/{$id}");
      }
      catch(Exception $e)
      {
        $this->fail('Exception: ' . $e->getMessage());
      }
      $fullEmail = json_decode($response->getBody());
      return $fullEmail;
    }
docs: Get Full Email
  
  Returns the full content of an email
  
  @param string $id ID from the header
  @return mixed Returns a JSON encoded Email