python-async-future.py

import asyncio
from nats.aio.client import Client as NATS

async def run(loop):
    nc = NATS()

    await nc.connect("nats://demo.nats.io:4222", loop=loop)

    future = asyncio.Future()
    async def cb(msg):
        nonlocal future
        future.set_result(msg)

    await nc.subscribe("updates", cb=cb)
    await nc.publish("updates", b'OK')
    await nc.flush()

    # Wait for message to come in
    msg = await asyncio.wait_for(future, 1)
    print("[Received]:", msg)

    await nc.close()

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(run(loop))
    loop.close()