From 453efe10c05666091ae94cc6847cbc1e3376e49d Mon Sep 17 00:00:00 2001
From: Sam Bull <git@sambull.org>
Date: Thu, 22 Jun 2023 20:06:29 +0100
Subject: [PATCH] Update asyncio-eventloop.rst

---
 Doc/library/asyncio-eventloop.rst | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
index 8d0022cc66daac..38f2e2f510c176 100644
--- a/Doc/library/asyncio-eventloop.rst
+++ b/Doc/library/asyncio-eventloop.rst
@@ -895,6 +895,9 @@ TLS Upgrade
    object only because the coder caches *protocol*-side data and sporadically
    exchanges extra TLS session packets with *transport*.
 
+   In some situations (e.g. when the passed transport is already closing) this
+   may return ``None``.
+
    Parameters:
 
    * *transport* and *protocol* instances that methods like