Future does not have _set_result method

[apatrushev]

Context

Future created here:

aiogram/aiogram/dispatcher/dispatcher.py

Line 80 in 58a8f43

self._close_waiter = loop.create_future()

... later used to _set_result, but asyncio.Future does not have such method:

aiogram/aiogram/dispatcher/dispatcher.py

Line 302 in 58a8f43

self._close_waiter._set_result(None)