The name of a field in the search index. Field names must begin with a letter and can contain the following characters: a-z (lowercase),
            0-9, and _ (underscore). Uppercase letters and hyphens are not allowed. The name "score" is reserved and cannot be specified as field or
            expression name.
             
            
Constraints:
 Declaration Syntax
 Declaration Syntax| C# | 
public string IndexFieldName { get; set; }