private static string toPersianNumbersUsingReplace(string data)
{
    if (string.IsNullOrWhiteSpace(data)) return string.Empty;
    return
      data
        .Replace("0", "\u06F0")
        .Replace("1", "\u06F1")
        .Replace("2", "\u06F2")
        .Replace("3", "\u06F3")
        .Replace("4", "\u06F4")
        .Replace("5", "\u06F5")
        .Replace("6", "\u06F6")
        .Replace("7", "\u06F7")
        .Replace("8", "\u06F8")
        .Replace("9", "\u06F9");
}

        private static string toPersianNumbersUsingReplace(string data)
        {
            if (string.IsNullOrWhiteSpace(data)) return string.Empty;
            return
                toEnglishNumbers(data)
                .Replace("0", "\u06F0")
                .Replace("1", "\u06F1")
                .Replace("2", "\u06F2")
                .Replace("3", "\u06F3")
                .Replace("4", "\u06F4")
                .Replace("5", "\u06F5")
                .Replace("6", "\u06F6")
                .Replace("7", "\u06F7")
                .Replace("8", "\u06F8")
                .Replace("9", "\u06F9");
        }

        private static string toEnglishNumbers(string data)
        {
            if (string.IsNullOrWhiteSpace(data)) return string.Empty;
            return
               data.Replace("\u0660", "0") //٠
                   .Replace("\u06F0", "0") //۰
                   .Replace("\u0661", "1") //١
                   .Replace("\u06F1", "1") //۱
                   .Replace("\u0662", "2") //٢
                   .Replace("\u06F2", "2") //۲
                   .Replace("\u0663", "3") //٣
                   .Replace("\u06F3", "3") //۳
                   .Replace("\u0664", "4") //٤
                   .Replace("\u06F4", "4") //۴
                   .Replace("\u0665", "5") //٥
                   .Replace("\u06F5", "5") //۵
                   .Replace("\u0666", "6") //٦
                   .Replace("\u06F6", "6") //۶
                   .Replace("\u0667", "7") //٧
                   .Replace("\u06F7", "7") //۷
                   .Replace("\u0668", "8") //٨
                   .Replace("\u06F8", "8") //۸
                   .Replace("\u0669", "9") //٩
                   .Replace("\u06F9", "9"); //۹
        }

  .Replace("\u0669", "9") //٩

  .Replace('\u0669', '9') //٩

        private static string toPersianNumbersUsingStringBuilder(string data)
        {
            if (string.IsNullOrWhiteSpace(data)) return string.Empty;

            var strBuilder = new StringBuilder(data);
            for (var i = 0; i < strBuilder.Length; i++)
            {
                switch (strBuilder[i])
                {
                    case '0':
                    case '\u0660':
                        strBuilder[i] = '\u06F0';
                        break;

                    case '1':
                    case '\u0661':
                        strBuilder[i] = '\u06F1';
                        break;

                    case '2':
                    case '\u0662':
                        strBuilder[i] = '\u06F2';
                        break;

                    case '3':
                    case '\u0663':
                        strBuilder[i] = '\u06F3';
                        break;

                    case '4':
                    case '\u0664':
                        strBuilder[i] = '\u06F4';
                        break;

                    case '5':
                    case '\u0665':
                        strBuilder[i] = '\u06F5';
                        break;

                    case '6':
                    case '\u0666':
                        strBuilder[i] = '\u06F6';
                        break;

                    case '7':
                    case '\u0667':
                        strBuilder[i] = '\u06F7';
                        break;

                    case '8':
                    case '\u0668':
                        strBuilder[i] = '\u06F8';
                        break;

                    case '9':
                    case '\u0669':
                        strBuilder[i] = '\u06F9';
                        break;

                    default:
                        strBuilder[i] = strBuilder[i];
                        break;
                }
            }

            return strBuilder.ToString();
        }

        private static string toPersianNumbersUsingToCharArray(string data)
        {
            if (string.IsNullOrWhiteSpace(data)) return string.Empty;

            var letters = data.ToCharArray();
            for (var i = 0; i < letters.Length; i++)
            {
                switch (letters[i])
                {
                    case '0':
                    case '\u0660':
                        letters[i] = '\u06F0';
                        break;

                    // مانند قبل

                }
            }

            return new string(letters);
        }

        private static string toPersianNumbersUsingStringCreate(string data)
        {
            if (string.IsNullOrWhiteSpace(data)) return string.Empty;

            return string.Create(data.Length, data, (chars, context) =>
            {
                for (var i = 0; i < data.Length; i++)
                {
                    switch (context[i])
                    {
                        case '0':
                        case '\u0660':
                            chars[i] = '\u06F0';
                            break;

                    // مانند قبل

                    }
                }
            });
        }

public static string Create<TState> (int length, TState state, System.Buffers.SpanAction<char,TState> action);

 return string.Create(data.Length, data, (chars, context) => {});

 int a = default(int);

var number = default(int); // 0
var date = default(DateTime); // DateTime.MinValue
var obj = default(object); // null

int a = default; // 0
Guid guid = default; // 00000000-0000-0000-0000-000000000000

 var ages = new[] {18, default, 50};

 var ages = new[] { default };

string s = default;
if(s == default)
{

}

int a = default;
var x = a > 0 ? default : 1.5;

public class Question
{
    public string FileId { set; get; }
}

            using (var store = new DocumentStore
            {
                Url = "http://localhost:8080"
            }.Initialize())
            {
                using (var session = store.OpenSession())
                {
                    store.DatabaseCommands.PutAttachment(key: "file/1",
                                                         etag: null,
                                                         data: System.IO.File.OpenRead(@"D:\Prog\packages.config"),
                                                         metadata: new RavenJObject
                                                         { 
                                                            { "Description", "توضیحات فایل" }
                                                         });
                    var question = new Question
                    {
                        By = "users/Vahid",
                        Title = "Raven Intro",
                        Content = "Test....",
                        FileId = "file/1"
                    };
                    session.Store(question);

                    session.SaveChanges();
                }
            }

 Request # 2: PUT   - 200 ms - <system> - 201 - /static/file/1

            using (var store = new DocumentStore
            {
                Url = "http://localhost:8080"
            }.Initialize())
            {
                using (var session = store.OpenSession())
                {
                    var question = session.Load<Question>("questions/97");
                    var file1 = store.DatabaseCommands.GetAttachment(question.FileId);
                    Console.WriteLine(file1.Size);
                }
            }

            using (var store = new DocumentStore
            {
                Url = "http://localhost:8080"
            }.Initialize())
            {
                using (var session = store.OpenSession())
                {
                    store.DatabaseCommands.Patch(key: "questions/97",
                                                 patches: new[]
                                                          {
                                                             new PatchRequest
                                                             {
                                                                Type = PatchCommandType.Add,
                                                                Name = "Answers",
                                                                Value = RavenJObject.FromObject(new Answer{ By= "users/Vahid", Content="data..."})
                                                             }
                                                          });
                }
            }

 PM> Install-Package RavenDB.Bundles.CascadeDelete -Pre

var comment = new Comment
{
   PostId = post.Id
};
session.Store(comment);

session.Advanced.GetMetadataFor(post)["Raven-Cascade-Delete-Documents"] = RavenJToken.FromObject(new[] { comment.Id });
session.Advanced.GetMetadataFor(post)["Raven-Cascade-Delete-Attachments"] =  RavenJToken.FromObject(new[] { "picture/1" });

session.SaveChanges();

 PM> Install-Package RavenDB.Bundles.Versioning

session.Store(new VersioningConfiguration
{
  Exclude = false,
  Id = "Raven/Versioning/DefaultConfiguration",
  MaxRevisions = 5
});

 var lastThreeVersions = session.Advanced.GetRevisionsFor<BlogPost>(post.Id, 0, 3);