在使用ProcessPoolExecutor的同时使用asyncio时，容易出现task未执行完毕便调用ProcessPoolExecutor的shutdown导致程序意外退出的问题。

解决方法是使用asyncio的asyncio.wait方法，等待所有task执行完毕后再调用ProcessPoolExecutor的shutdown。代码示例如下：

import asyncio
import concurrent.futures

async def run_in_executor(executor):
    return await asyncio.get_event_loop().run_in_executor(executor, some_blocking_io)

async def main():
    loop = asyncio.get_event_loop()
    executor = concurrent.futures.ProcessPoolExecutor()
    tasks = [loop.create_task(run_in_executor(executor)) for _ in range(5)]

    await asyncio.wait(tasks)
    executor.shutdown(wait=True)

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