concurrent.futures.Future.add_done_callback: calling thread description error.

asyncio.run_coroutine_threadsafe will return a concurrent.futures.Future.
And according to its doc concurrent.futures.Future.add_done_callback() :

Added callables are called in the order that they were added and are always ** called in a thread belonging to the process that added them. **

But acually, the callback is called in where Future.set_result() is called according to its source.

Linked PRs

• gh-122678

從 concurrent.futures.Future.add_done_callback() 文件以及透過 asyncio.run_coroutine_threadsafe 達成的行為開始；將措辭與 Future.set_result() 的原始碼路徑進行比較。在進行變更之前考量現有的關聯 PR，並確保文件準確描述回呼執行所在的執行緒，即視為完成。