Add placeholder while loading to ChatFeed

[ahuang11]

To indicate activity while some callbacks are blocking, I've been wanting to have some control over the loading spinner, and have it persist.

Screen.Recording.2024-07-29.at.2.07.19.PM.mov

import asyncio
import panel as pn

pn.extension()

async def callback(message):
    await asyncio.sleep(2)
    return message


chat = pn.chat.ChatInterface(callback=callback, callback_exception="verbose", loading=True)
chat.servable()

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.24%. Comparing base (310309e) to head (174cb2b).
Report is 20 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7042      +/-   ##
==========================================
+ Coverage   81.79%   82.24%   +0.44%     
==========================================
  Files         326      326              
  Lines       48307    48327      +20     
==========================================
+ Hits        39514    39745     +231     
+ Misses       8793     8582     -211     

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[philippjfr]

How does this interact with the usual loading spinner?

[ahuang11]

Do you mean something like pn.Column("Hello", loading=True)?

I don't think anything gets overlaid on ChatInterface besides the individual buttons
pn.chat.ChatInterface("Hello", loading=True).show()