bpo-44508: [Doc] Document failure mode for loop.call_soon_threadsafe (GH-27688)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>
(cherry picked from commit 3240bc62f4e0afa09964f3afc845697f0a0806b9)

Co-authored-by: meowmeowmeowcat <meowmeowcat1211@gmail.com>

diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
index b1609f7bb77f218434cebfaf45b2ed2c065eb9cd..eee8095bd4c0fbafff9d9a0a652cda15e6f07b45 100644 (file)
--- a/Doc/library/asyncio-eventloop.rst
+++ b/Doc/library/asyncio-eventloop.rst
@@ -216,6 +216,10 @@ Scheduling callbacks
    A thread-safe variant of :meth:`call_soon`.  Must be used to
    schedule callbacks *from another thread*.
 
+   Raises :exc:`RuntimeError` if called on a loop that's been closed.
+   This can happen on a secondary thread when the main application is
+   shutting down.
+
    See the :ref:`concurrency and multithreading <asyncio-multithreading>`
    section of the documentation.