bpo-36794: Document that Lock.acquire is fair. (GH-13082)
https://bugs.python.org/issue36794
diff --git a/Doc/library/asyncio-sync.rst b/Doc/library/asyncio-sync.rst
index e3f18cc..79f6b02 100644
--- a/Doc/library/asyncio-sync.rst
+++ b/Doc/library/asyncio-sync.rst
@@ -66,6 +66,13 @@
This method waits until the lock is *unlocked*, sets it to
*locked* and returns ``True``.
+ When more than one coroutine is blocked in :meth:`acquire`
+ waiting for the lock to be unlocked, only one coroutine
+ eventually proceeds.
+
+ Acquiring a lock is *fair*: the coroutine that proceeds will be
+ the first coroutine that started waiting on the lock.
+
.. method:: release()
Release the lock.