Fixes issue discussed over at https://nullprogram.com/blog/2020/05/24/

latency_with_unsync.py

import asyncio
import time

from unsync import unsync


@unsync
async def heartbeat():
    while True:
        start = time.time()
        await asyncio.sleep(1)
        delay = time.time() - start - 1
        print(f'heartbeat delay = {delay:.3f}s')


JOB_DURATION = 0.01  # 10ms


@unsync()
def process():
    time.sleep(JOB_DURATION)  # simulate CPU time
    return True


JOB_COUNT = 200


@unsync
async def main():
    # noinspection PyAsyncCall
    heartbeat()

    await asyncio.sleep(2.5)

    print('begin processing')
    count = JOB_COUNT
    tasks = [process() for _ in range(count)]
    for t in tasks:
        await t

    await asyncio.sleep(5)


if __name__ == '__main__':
    main().result()