readFrom method
Creates a payload from the specified header stream.
Implementation
@override
void readFrom(MqttByteBuffer payloadStream) {
var payloadBytesRead = 0;
final payloadLength = header!.messageSize - variableHeader!.length;
// Read all the topics and qos subscriptions from the message payload
while (payloadBytesRead < payloadLength) {
final topic = payloadStream.readMqttStringM();
payloadBytesRead += topic.length + 2; // +2 = Mqtt string length bytes
addSubscription(topic);
}
}