#!/usr/bin/env python


import asyncio


class Stream(object):
    def __init__(self):
        self._queue = asyncio.Queue(1)
        self._num = 0
        self._last_read_num = 0

    async def write(self, item):
        self._num += 1
        await self._queue.put((self._num, item))

    async def read(self):
        num, item = await self._queue.get()
        print(f'num={num}, last_read_num={self._last_read_num}')
        assert num == self._last_read_num + 1
        self._last_read_num = num

        await asyncio.sleep(0.0)

        return item


async def produce(stream):
    loop = asyncio.get_running_loop()
    cnt = 0
    while True:
        loop.create_task(stream.write('abc'))
        cnt += 1
        if cnt == 32:
            await asyncio.sleep(0.0)
            cnt = 0


async def main():
    stream = Stream()
    asyncio.create_task(produce(stream))

    while True:
        await stream.read()


asyncio.run(main())