Copies the object if it has been modified since the specified time, otherwise returns a PreconditionFailed.
            
 Declaration Syntax
 Declaration Syntax| C# | 
public DateTime ModifiedSinceDate { get; set; }
 Remarks
 Remarks
            Copies the object if it has been modified since the
            specified time; otherwise returns a 412 (failed condition).
            Constraints: This property can be used with ETagToNotMatch,
            but cannot be used with other conditional copy properties.