Copy byte array as block in Guid ctor

Author: xtqqczze

src/libraries/System.Private.CoreLib/src/System/Guid.cs

@@ -127,17 +127,13 @@ public Guid(int a, short b, short c, byte[] d)
                 throw new ArgumentException(SR.Format(SR.Arg_GuidArrayCtor, "8"), nameof(d));
             }
 
+            Unsafe.SkipInit(out this);
+
             _a = a;
             _b = b;
             _c = c;
-            _d = d[0];
-            _e = d[1];
-            _f = d[2];
-            _g = d[3];
-            _h = d[4];
-            _i = d[5];
-            _j = d[6];
-            _k = d[7];
+
+            Unsafe.CopyBlockUnaligned(ref _d, ref MemoryMarshal.GetArrayDataReference(d), 8);
         }
 
         // Creates a new GUID initialized to the value represented by the