Refactor serializer benchmark to allow fair comparisons.

Source/MQTTnet/Adapter/MqttChannelAdapter.cs

@@ -192,7 +192,7 @@ namespace MQTTnet.Adapter
                     bodyOffset += readBytes;
                 } while (bodyOffset < body.Length);
 
-                return new ReceivedMqttPacket(fixedHeader.Flags, new MqttPacketBodyReader(body));
+                return new ReceivedMqttPacket(fixedHeader.Flags, new MqttPacketBodyReader(body, 0));
             }
             finally
             {

Source/MQTTnet/Serializer/MqttPacketBodyReader.cs

@@ -8,9 +8,10 @@ namespace MQTTnet.Serializer
         private readonly byte[] _buffer;
         private int _offset;
 
-        public MqttPacketBodyReader(byte[] buffer)
+        public MqttPacketBodyReader(byte[] buffer, int offset)
         {
             _buffer = buffer;
+            _offset = offset;
         }
 
         public int Length => _buffer.Length - _offset;

Tests/MQTTnet.Benchmarks/SerializerBenchmark.cs

@@ -46,29 +46,17 @@ namespace MQTTnet.Benchmarks
         {
             for (var i = 0; i < 10000; i++)
             {
-                using (var headerStream = new MemoryStream(Join(_serializedPacket)))
+                using (var stream = new MemoryStream())
                 {
-                    var channel = new TestMqttChannel(headerStream);
+                    stream.Write(_serializedPacket.Array, _serializedPacket.Offset, _serializedPacket.Count);
+                    stream.Position = 0;
+
+                    var channel = new TestMqttChannel(stream);
 
                     var header = MqttPacketReader.ReadFixedHeaderAsync(channel, CancellationToken.None).GetAwaiter().GetResult();
-                    
+                    _serializer.Deserialize(new ReceivedMqttPacket(header.Flags, new MqttPacketBodyReader(_serializedPacket.Array, _serializedPacket.Count - header.RemainingLength)));
-                    using (var bodyStream = new MemoryStream(Join(_serializedPacket), (int)headerStream.Position, header.RemainingLength))
-                    {
-                        _serializer.Deserialize(new ReceivedMqttPacket(header.Flags, new MqttPacketBodyReader(bodyStream.ToArray())));
-                    }
                 }
             }
         }
-        
-        private static byte[] Join(params ArraySegment<byte>[] chunks)
-        {
-            var buffer = new MemoryStream();
-            foreach (var chunk in chunks)
-            {
-                buffer.Write(chunk.Array, chunk.Offset, chunk.Count);
-            }
-
-            return buffer.ToArray();
-        }
     }
 }

Tests/MQTTnet.Core.Tests/MqttPacketSerializerTests.cs

@@ -422,7 +422,7 @@ namespace MQTTnet.Core.Tests
                 
                 using (var bodyStream = new MemoryStream(Join(buffer1), (int)headerStream.Position, header.RemainingLength))
                 {
-                    var deserializedPacket = serializer.Deserialize(new ReceivedMqttPacket(header.Flags, new MqttPacketBodyReader(bodyStream.ToArray())));
+                    var deserializedPacket = serializer.Deserialize(new ReceivedMqttPacket(header.Flags, new MqttPacketBodyReader(bodyStream.ToArray(), 0)));
                     var buffer2 = serializer.Serialize(deserializedPacket);
 
                     Assert.AreEqual(expectedBase64Value, Convert.ToBase64String(Join(buffer2)));