send method
Implementation
Future<void> send(String request, String receiverPublicKey, String topic,
{int? ttl}) async {
final bridgeBase = _bridgeUrl;
var bridgeUrl = '$bridgeBase/$postPath?client_id=$_sessionId';
final ttlValue = ttl ?? defaultTtl;
bridgeUrl += '&to=$receiverPublicKey&ttl=$ttlValue&topic=$topic';
final xhr = HttpRequest();
xhr.open('POST', bridgeUrl);
xhr.setRequestHeader('Content-Type', 'application/json; charset=utf-8');
xhr.send(request);
}