Asyncio error when closing the program

[benvito]

Starting from version 0.21.0, an error began to appear when closing the application, regardless of the complexity of the application
OS: Windows 10 professional
main.py:

import flet as ft

async def main(page: ft.Page):
        page.add(ft.Text("Hello, Flet!"))

ft.app(target=main)

Output when im closing the app:

Traceback (most recent call last):
  File "d:/ProjectsProgramming/IvyTestBuild/app/main.py", line 6, in <module>
    ft.app(target=main)
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\site-packages\flet_runtime\app.py", line 70, in app
    return asyncio.run(
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\asyncio\runners.py", 
line 44, in run
    return loop.run_until_complete(main)
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 616, in run_until_complete
    return future.result()
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\site-packages\flet_runtime\app.py", line 207, in app_async
    await conn.close()
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\site-packages\flet_runtime\flet_socket_server.py", line 188, in close
    self.__executor.shutdown(wait=False, cancel_futures=True)
TypeError: shutdown() got an unexpected keyword argument 'cancel_futures'
Exception ignored in: <function _ProactorBasePipeTransport.__del__ at 0x000001EB8496F040>
Traceback (most recent call last):
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\asyncio\proactor_events.py", line 116, in __del__
    self.close()
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\asyncio\proactor_events.py", line 108, in close
    self._loop.call_soon(self._call_connection_lost, None)
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 719, in call_soon
    self._check_closed()
  File "C:\Users\ganya\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 508, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

[ndonkoHenri]

See this: #2848 (comment)