From 0ef7f07e12426ea68876747f235498961376b184 Mon Sep 17 00:00:00 2001
From: Brah McDude <77924970+brah-mcdude@users.noreply.github.com>
Date: Fri, 14 May 2021 16:43:18 +0300
Subject: [PATCH] Merge pull request #5011 from brah-mcdude/dev

Update TestScheduler.cs
---
 src/core/Akka.TestKit/TestScheduler.cs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/core/Akka.TestKit/TestScheduler.cs b/src/core/Akka.TestKit/TestScheduler.cs
index 8a224a8a80f..4315cc815a1 100644
--- a/src/core/Akka.TestKit/TestScheduler.cs
+++ b/src/core/Akka.TestKit/TestScheduler.cs
@@ -88,10 +88,14 @@ private void InternalSchedule(TimeSpan? initialDelay, TimeSpan delay, ICanTell r
         {
             var scheduledTime = _now.Add(initialDelay ?? delay).UtcTicks;
 
-            if (!_scheduledWork.TryGetValue(scheduledTime, out var tickItems))
+            ConcurrentQueue<ScheduledItem> tickItems;
+            while (!_scheduledWork.TryGetValue(scheduledTime, out tickItems))
             {
                 tickItems = new ConcurrentQueue<ScheduledItem>();
-                _scheduledWork.TryAdd(scheduledTime, tickItems);
+                if (_scheduledWork.TryAdd(scheduledTime, tickItems))
+                {
+                    break;
+                }
             }
             
             var type = message == null ? ScheduledItem.ScheduledItemType.Action : ScheduledItem.ScheduledItemType.Message;