loop.call_later doesnt work properly

import asyncio
import functools
import time


PROCESS_TIMEOUT = 1.1
loop = asyncio.get_event_loop()


def warn_slow_process(*args):
    print('warn slow process')


async def some_long_fun():
    print('entered some long fun, doing work')
    time.sleep(2.1)
    print('doing work done')


async def process_request():
    # Analog of `asyncio.wait_for` but without cancelling task
    waiter = loop.create_future()
    timeout_handle = loop.call_later(PROCESS_TIMEOUT, asyncio.tasks._release_waiter, waiter)
    cb = functools.partial(asyncio.tasks._release_waiter, waiter)

    fut = asyncio.ensure_future(some_long_fun(), loop=loop)
    fut.add_done_callback(cb)

    try:
        try:
            await waiter
        except asyncio.futures.CancelledError:
            fut.remove_done_callback(cb)
            fut.cancel()
            raise

        if fut.done():
            print('Fut done, returning res')
            return fut.result()
        else:
            print('Fut slow, attaching cb')
            fut.remove_done_callback(cb)
            fut.add_done_callback(warn_slow_process)
    finally:
        timeout_handle.cancel()

try:
    print('entering event loop')
    loop.run_until_complete(process_request())
finally:
    print('closing event loop')
    loop.close()