Python asyncio-如何延迟地链()从as\u completed()返回的结果?

在下面的代码示例中,我需要找到步骤3的解决方案):

import asyncio as aio
import random


async def produce_numbers(x):
    await aio.sleep(random.uniform(0, 3.0))
    return [x * x, x * x + 1, x * x + 2]


async def main():

    # Step 1) Create a list of unawaited coroutines.
    coros = [produce_numbers(i) for i in range(0, 10)]

    # Step 2) Create generator to return items in order of completion.
    futs = aio.as_completed(coros)  # type: generator

    # Step 3) Create a generator that returns every single number lazily.
    # This is the step I don't know how to accomplish.
    # I can't find a way to chain the lists that I get from each
    # `produce_numbers()` call together in a lazy manner.

    # Step 4) This loops should fire as soon as the first
    # `produce_numbers()` coroutine finished.
    for number in my_number_generator:
        print(number)


if __name__ == '__main__':
    loop = aio.get_event_loop()
    loop.run_until_complete(main())

也许在标准库中有一个我缺失的关键函数?