Rendering output from within async function does not work as intended

[and3rson]

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Description

When modifying outputs from async functions, modifying components attributes (and doing prints) works, but re-rendering outputs does not.

Reproduce

Consider code which attempts to re-render the output from within async function:

%gui asyncio
import asyncio
import ipywidgets as widgets

buttons = widgets.Output()
lines = widgets.Output()

display(buttons, lines)

async def func():
    for i in range(5):
        # Render new button
        buttons.clear_output()
        with buttons:
            display(widgets.Button(description=str(i)))
    
        # Append new line
        with lines:
            print(i)

_ = asyncio.ensure_future(func())

This re-renders the button 5 times and prints 5 messages as expected:

However, when adding a delay inside the function:

  ...
  async def func():
      for i in range(5):
+         await asyncio.sleep(0.1)
    
          # Render new button
          ...

...the button output never updates and gets stuck at initially rendered instance. However, prints still work fine:

Expected behavior

with some_output: display(...) should always update UI, irregardless from where it was called from.

Context

• ipywidgets version 8.1.2
• Operating System and version: Arch Linux
• Browser and version: Mozilla Firefox 125.0b6