// TODO: SEND MAIL
void _sendMail() async {
  if (!_formKey.currentState.validate()) {
    return;
  } else {
    _formKey.currentState.save();

    var _options = new GmailSmtpOptions()
    ..username = “mymailaddress@gmail.com"
    ..password = “myPassword”;

    var _emailTransport = new SmtpTransport(_options);
    var _envelope = new Envelope()
    ..from = "mymailaddress@gmail.com"
    ..recipients.add(_receiverMailAddress)
      ..subject = "${_userDekontDetails[0][0].toString()} - Receipt”
      ..attachments.add(await new Attachment(file: await new File('$newDekontImage')))
      ..text = "${_userDekontDetails[0][0].toString()} - Receipt"
      ..html = '<h3>${_userDekontDetails[0][0].toString()} Receipt.</h3>'
          '<p>Hi, registered under my name, I am sending the receipt (${widget._currentUserReceiptNo}) with attached to this mail.</p>'
          '<p></p>'
          '<h5>Regards, </br></h5>'
          '${_userDekontDetails[0][0].toString()}';

    _emailTransport.send(_envelope)
      ..then((envelope) => print('Email sent'))
      ..catchError((e) => print('Error occured: $e'));
  }
}