lib/protocols/wns.js
function sendRequiredErrors(sender, missingProps) {
  _.forEach(missingProps, function (prop) {
    sender.emit('error', prop + ' is missing');
  });
}
function sendRequiredErrors(sender, missingProps) {
  _.forEach(missingProps, function (prop) {
    sender.emit('error', prop + ' is missing');
  });
}
send an error for each missing properties