add debug info

src/TensorFlowHub/MnistDataSet.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Text;
 using NumSharp;
 using Tensorflow;
@@ -21,7 +22,12 @@ namespace Tensorflow.Hub
 
             images = images.reshape(images.shape[0], images.shape[1] * images.shape[2]);
             images = images.astype(dataType);
+            // for debug np.multiply performance
+            var sw = new Stopwatch();
+            sw.Start();
             images = np.multiply(images, 1.0f / 255.0f);
+            sw.Stop();
+            Console.WriteLine($"{sw.ElapsedMilliseconds}ms");
             Data = images;
 
             labels = labels.astype(dataType);

src/TensorFlowNET.Core/Status/Status.cs

@@ -55,7 +55,7 @@ namespace Tensorflow
                 Console.WriteLine(Message);
                 if (throwException)
                 {
-                    // throw new Exception(Message);
+                    throw new Exception(Message);
                 }
             }
         }