Push Parquet files to Parquet project

Author: Ivan Matantsev

src/Microsoft.ML.Data/Commands/DataCommand.cs

@@ -403,7 +403,7 @@ internal static class LoaderUtils
         /// <summary>
         /// Saves <paramref name="loader"/> to the specified <paramref name="file"/>.
         /// </summary>
-        internal static void SaveLoader(IDataLoader loader, IFileHandle file)
+        public static void SaveLoader(IDataLoader loader, IFileHandle file)
         {
             Contracts.CheckValue(loader, nameof(loader));
             Contracts.CheckValue(file, nameof(file));
@@ -418,7 +418,7 @@ internal static void SaveLoader(IDataLoader loader, IFileHandle file)
         /// <summary>
         /// Saves <paramref name="loader"/> to the specified <paramref name="stream"/>.
         /// </summary>
-        internal static void SaveLoader(IDataLoader loader, Stream stream)
+        public static void SaveLoader(IDataLoader loader, Stream stream)
         {
             Contracts.CheckValue(loader, nameof(loader));
             Contracts.CheckValue(stream, nameof(stream));

src/Microsoft.ML.Data/DataView/ZipBinding.cs

@@ -12,6 +12,7 @@ namespace Microsoft.ML.Data
     /// A convenience class for concatenating several schemas together.
     /// This would be necessary when combining IDataViews through any type of combining operation, for example, zip.
     /// </summary>
+    [BestFriend]
     internal sealed class ZipBinding
     {
         private readonly Schema[] _sources;