async/await in subscriber callback

edit

I have a ros node that needs to communicate with a non-ros over a tcp asynchronous socket connection. This node will be subscribed to a variety of topics and needs to send data over the socket connection when a message is received (by calling the socket writer within the subscriber callback).

My issue is that I cannot use async/await syntax for a subscriber callback since rospy.Subscriber() does not allow the callback to be awaited.

Ubuntu20 Ros Noetic Python 3.8.2

Here's a MWE:

A generic publisher, representing one of several nodes generating data I eventually want to send over the socket:

 #!/usr/bin/env python3

import rospy 
from std_msgs.msg import String

def sample_publisher():
    rospy.init_node('question_pub')
    pub = rospy.Publisher('topic_name', String, queue_size=10)
    rate = rospy.Rate(1)
    msg = String(data="sample message")

    rospy.loginfo("starting publish loop")
    while not rospy.is_shutdown():
        pub.publish(msg)
        rospy.loginfo("finished pub'in")
        rate.sleep()

if __name__ == '__main__':
    sample_publisher()

The subscriber in question:

#!/usr/bin/env python3


import rospy
from std_msgs.msg import String
import asyncio

class listener_handle:
    def __init__(self):
        rospy.init_node('question_sub')
        self.server_address = '127.0.0.1'
        self.port = 51222

    def activate_subscribers(self):
        #separated to ensure async writer is defined before first message
        rospy.Subscriber("topic_name", String, self.callback)

    async def connect2server(self):
        self.reader, self.writer = await asyncio.open_connection(self.server_address, self.port)

    async def async_spin(self):
        rospy.loginfo("beginning node spin")
        while not rospy.is_shutdown():
            #want bidirectional messages
            recvData = await self.reader.read(100)
            rospy.loginfo("got {} from socket server".format(recvData.decode()))

    async def callback(self, data):
        rospy.loginfo("callback received value of {}".format(data.data))
        self.writer.write(data.data.encode())
        await self.writer.drain()


async def main():
    h = listener_handle()
    await h.connect2server()
    h.activate_subscribers()
    await h.async_spin()

if __name__ == '__main__':
    asyncio.run(main())

which errors on startup with

/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py:750: RuntimeWarning: coroutine 'listener_handle.callback' was never awaited
  cb(msg)

and, for reference, the socket server I'm trying to connect to:

#!/usr/bin/env python3

import asyncio

async def handle_echo(reader, writer):
    print("client connected, waiting for msg")
    data = await reader.read(100)
    message = data.decode()

    print("Received {}".format(message))

    writer.write(data)
    #immediately send back to subscriber client
    await writer.drain()
    print("Close the connection")
    writer.close()

async def main():
    server = await asyncio.start_server(
        handle_echo, '127.0.0.1', 51222)

    print("server started up")
    async with server:
        await server.serve_forever()

asyncio.run(main())

I've attempted to make the subscriber asynchronous but it is not awaitable.

I know the subscribers themselves work asynchronously, but I looked for a few hours and was unable to find any examples using the asyncio library like this.

How can I use await within a rospy subscriber callback? Thanks in advance!