From a202d33b3e4d0aab3ca007baa800809973b31c9f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B6nke=20Ludwig?= <sludwig@rejectedsoftware.com>
Date: Sat, 13 Apr 2019 17:01:50 +0200
Subject: [PATCH] Fix a (harmless) race-condition.

ThreadLocalWaiter.unused may only be accessed from the owner thread.
---
 source/vibe/core/sync.d | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/vibe/core/sync.d b/source/vibe/core/sync.d
index dffc335..11afc0d 100644
--- a/source/vibe/core/sync.d
+++ b/source/vibe/core/sync.d
@@ -1063,8 +1063,8 @@ struct ManualEvent {
 		auto drv = eventDriver;
 		m_waiters.lock.active.iterate((ThreadWaiter w) {
 			() @trusted { logTrace("waiter %s", cast(void*)w); } ();
-			if (w.unused) return true;
 			if (w.m_driver is drv) {
+				if (w.unused) return true;
 				lw = w;
 				lw.addRef();
 			} else {