Update Program.cs

Author: CESARDELATORRE

samples/csharp/getting-started/MulticlassClassification_Iris/IrisClassification/IrisClassificationConsoleApp/Program.cs

@@ -46,7 +46,10 @@ private static void BuildTrainEvaluateAndSaveModel(MLContext mlContext)
             var dataProcessPipeline = mlContext.Transforms.Concatenate("Features", "SepalLength",
                                                                                    "SepalWidth",
                                                                                    "PetalLength",
-                                                                                   "PetalWidth").AppendCacheCheckpoint(mlContext);
+                                                                                   "PetalWidth")
+                                                                       .AppendCacheCheckpoint(mlContext); 
+                                                                       // Use in-memory cache for small/medium datasets to lower training time. 
+                                                                       // Do NOT use it (remove .AppendCacheCheckpoint()) when handling very large datasets. 
 
             // STEP 3: Set the training algorithm, then append the trainer to the pipeline  
             var trainer = mlContext.MulticlassClassification.Trainers.StochasticDualCoordinateAscent(labelColumn: "Label", featureColumn: "Features");
@@ -119,4 +122,4 @@ private static void TestSomePredictions(MLContext mlContext)
 
         }
     }
-}
+}