Refactor removal from blocking queue.

Source/MQTTnet.Extensions.ManagedClient/ManagedMqttClient.cs

@@ -300,7 +300,7 @@ namespace MQTTnet.Extensions.ManagedClient
                     //in the queue is equal to this message, then it's safe to remove
                     //it from the queue.  If not, that means this.PublishAsync has already
                     //removed it, in which case we don't want to do anything.
-                    _messageQueue.RemoveFirstIfEqual(message, IdsAreEqual);
+                    _messageQueue.RemoveFirst(i => i.Id.Equals(message.Id));
                 }
                 _storageManager?.RemoveAsync(message).GetAwaiter().GetResult();
             }
@@ -321,7 +321,7 @@ namespace MQTTnet.Extensions.ManagedClient
                     //with prior behavior in that way.
                     lock (_messageQueue) //lock to avoid conflict with this.PublishAsync
                     {
-                        _messageQueue.RemoveFirstIfEqual(message, IdsAreEqual);
+                        _messageQueue.RemoveFirst(i => i.Id.Equals(message.Id));
                     }
                 }
             }
@@ -335,11 +335,6 @@ namespace MQTTnet.Extensions.ManagedClient
                 ApplicationMessageProcessed?.Invoke(this, new ApplicationMessageProcessedEventArgs(message, transmitException));
             }
         }
-        
-        private static bool IdsAreEqual(ManagedMqttApplicationMessage message1, ManagedMqttApplicationMessage message2)
-        {
-            return message1.Id.Equals(message2.Id);
-        }
 
         private async Task SynchronizeSubscriptionsAsync()
         {

Source/MQTTnet/Internal/BlockingQueue.cs

@@ -77,11 +77,13 @@ namespace MQTTnet.Internal
             }
         }
 
-        public void RemoveFirstIfEqual(TItem item, Func<TItem, TItem, bool> areEqual)
+        public void RemoveFirst(Predicate<TItem> match)
         {
+            if (match == null) throw new ArgumentNullException(nameof(match));
+
             lock (_syncRoot)
             {
-                if (_items.Count > 0 && areEqual(_items.First.Value, item))
+                if (_items.Count > 0 && match(_items.First.Value))
                 {
                     _items.RemoveFirst();
                 }