### Put the below into a separate server.py file


import asyncio


class EchoServerProtocol(asyncio.DatagramProtocol):
    def connection_made(self, transport):
        self.transport = transport

    def datagram_received(self, data, addr):
        message = data.decode()
        print('Received %r from %s' % (message, addr))
        print('Send %r to %s' % (message, addr))

        print('Server transport closing due to client abort?', self.transport.is_closing())
        self.transport.sendto(data, addr)

    def error_received(self, exc):
        print("Exception thrown caught by 'error_received': %s" % exc)


async def main():
    print("Starting UDP server")

    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    # Has no effect on the occurrence of this issue
    loop.set_debug(True)

    # One protocol instance will be created to serve all
    # client requests.
    transport, protocol = await loop.create_datagram_endpoint(
        lambda: EchoServerProtocol(),
        local_addr=('127.0.0.1', 9999))

    try:
        await asyncio.sleep(3600)  # Serve for 1 hour.
    finally:
        transport.close()


asyncio.run(main())



### Put the below into a separate client.py file


import asyncio


class EchoClientProtocol:

    def __init__(self, message, on_con_lost):
        self.message = message
        self.on_con_lost = on_con_lost
        self.transport = None

    def connection_made(self, transport: asyncio.DatagramTransport):
        self.transport = transport
        print('Send:', self.message)
        self.transport.sendto(self.message.encode())

        # Try to force the server to raise the error
        # 'No services is operation at the destination network endpoint on the remote system'
        self.transport.abort()

    def datagram_received(self, data, addr):
        print("Received:", data)

        print("Close the socket")
        self.transport.close()

    def error_received(self, exc):
        print('Error received:', exc)

    def connection_lost(self, exc):
        print("Connection closed")
        self.on_con_lost.set_result(True)


async def main():
    # Get a reference to the event loop as we plan to use
    # low-level APIs.
    loop = asyncio.get_running_loop()

    # Uncomment me to see the error disappear!!
    # loop.set_debug(True)

    on_con_lost = loop.create_future()
    message = "Hello World!"

    transport, protocol = await loop.create_datagram_endpoint(
        lambda: EchoClientProtocol(message, on_con_lost),
        remote_addr=('127.0.0.1', 9999))

    try:
        await on_con_lost
    finally:
        transport.close()


asyncio.run(main())