mqttsn 0.0.4

## Python Client for MQTT-SN brokers

### Usage examples

```python
from mqttsn.client import Client, Callback

import sys


class MyCallback(Callback):
def message_arrived(self, topic_name, payload, qos, retained, msgid):
print(f'{self} | topic_name: {topic_name} | payload: {payload} | '
f'qos {qos} | retained {retained} | msgid {msgid}',
file=sys.stderr)

return True


if __name__ == '__main__':
aclient = Client("linh", port=1883)
aclient.register_callback(MyCallback())
aclient.connect()

rc, topic1 = aclient.subscribe("topic1")
print("topic id for topic1 is", topic1)

rc, topic2 = aclient.subscribe("topic2")
print("topic id for topic2 is", topic2)

aclient.publish(topic1, "aaaa", qos=0)
aclient.publish(topic2, "bbbb", qos=0)

aclient.unsubscribe("topic1")

aclient.publish(topic2, "cccc", qos=0)
aclient.publish(topic1, "dddd", qos=0)

aclient.disconnect()
```