What's "method 'poll' of 'select.epoll' objects"?

Question

I added the following to print the performance stats

import cProfile
import pstats
pr = cProfile.Profile()
pr.enable()

And the output shows most of the time were used by method 'poll' of 'select.epoll' objects. What is it?

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     1045    8.123    0.008    8.123    0.008 {method 'poll' of 'select.epoll' objects}
      723    0.865    0.001    0.865    0.001 {method 'recv' of '_socket.socket' objects}
      500    0.109    0.000    0.109    0.000 encoder.py:204(iterencode)
      540    0.066    0.000    0.066    0.000 {method 'acquire' of '_thread.lock' objects}
     1045    0.012    0.000    9.257    0.009 base_events.py:1335(_run_once)
     2843    0.006    0.000    1.111    0.000 events.py:143(_run)
      500    0.005    0.000    0.115    0.000 encoder.py:182(encode)
     1045    0.005    0.000    8.129    0.008 selectors.py:428(select)
      501    0.004    0.000    0.004    0.000 events.py:638(_get_running_loop)
      500    0.004    0.000    0.008    0.000 futures.py:381(_chain_future)
     1000    0.004    0.000    0.214    0.000 test.py:29(parse_and_save_article)
     4001    0.003    0.000    0.003    0.000 {built-in method builtins.hasattr}
     2001    0.003    0.000    0.006    0.000 base_events.py:594(_call_soon)
      500    0.003    0.000    0.016    0.000 futures.py:361(_copy_future_state)
      342    0.002    0.000    0.868    0.003 selector_events.py:138(_read_from_self)
     2001    0.002    0.000    0.008    0.000 base_events.py:564(call_soon)
     2001    0.002    0.000    0.002    0.000 events.py:104(__init__)
      500    0.002    0.000    0.076    0.000 thread.py:114(submit)
     4000    0.002    0.000    0.005    0.000 base_futures.py:23(isfuture)
      500    0.002    0.000    0.004    0.000 base_events.py:277(create_task)
     3010    0.002    0.000    0.003    0.000 threading.py:239(__enter__)
      500    0.002    0.000    0.012    0.000 futures.py:420(wrap_future)
     1000    0.002    0.000    0.095    0.000 test.py:50(run)

I created a decorator to convert synchronous functions to async functions.

def wrap(func):
    @wraps(func)
    async def run(*args, loop=None, executor=None, **kwargs):
        if loop is None:
            loop = asyncio.get_event_loop()
        pfunc = partial(func, *args, **kwargs)
        return await loop.run_in_executor(executor, pfunc)
    return run