Performance optimizations

MQTTnet.Core/Serializer/ByteReader.cs

@@ -4,36 +4,42 @@ namespace MQTTnet.Core.Serializer
 {
     public class ByteReader
     {
+        private readonly int _source;
         private int _index;
-        private readonly int _byte;
 
-        public ByteReader(byte @byte)
+        public ByteReader(int source)
         {
-            _byte = @byte;
+            _source = source;
         }
 
         public bool Read()
         {
             if (_index >= 8)
             {
-                throw new InvalidOperationException("End of the byte reached.");
+                throw new InvalidOperationException("End of byte reached.");
             }
 
-            var result = ((1 << _index) & _byte) > 0;
+            var result = ((1 << _index) & _source) > 0;
             _index++;
-
             return result;
         }
 
         public byte Read(int count)
         {
+            if (_index + count > 8)
+            {
+                throw new InvalidOperationException("End of byte will be reached.");
+            }
+
             var result = 0;
             for (var i = 0; i < count; i++)
             {
-                if (Read())
+                if (((1 << _index) & _source) > 0)
                 {
                     result |= 1 << i;
                 }
+
+                _index++;
             }
 
             return (byte)result;