code: func (m *MailYak) MimeBuf() (*bytes.Buffer, error) {
  	buf, err := m.buildMime()
  	if err != nil {
  		return nil, err
  	}
  	return buf, nil
  }
docs: // MimeBuf returns the buffer containing all the RAW MIME data.
  //
  // MimeBuf is typically used with an API service such as Amazon SES that does
  // not use an SMTP interface.