From 75df988d8a019af94d5a5928ec825da341bbbe28 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 13 May 2021 17:08:57 +0200
Subject: [PATCH] Document safety of unsafe Sync impl

---
 src/lib.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/lib.rs b/src/lib.rs
index f5b3d82..499b6c7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -190,6 +190,7 @@ impl fmt::Debug for LazyMutexId {
     }
 }
 
+/// Safety: the UnsafeCell is guaranteed to only be accessed mutably from a `Once`.
 unsafe impl Sync for LazyMutexId {}
 
 impl Deref for LazyMutexId {