c#-record

record.cs

//the data modifier transforms the class into a record
//the constructor and destructor are not relevant for the example but make it easier 
public data class Person 
{ 
    string FirstName; 
    string LastName; 
    public Person(string firstName, string lastName) 
      => (FirstName, LastName) = (firstName, lastName);
    public void Deconstruct(out string firstName, out string lastName) 
      => (firstName, lastName) = (FirstName, LastName);
}

var person = new Person("Han", "Solo");

//the with expression gets a "patch function" which
//creates a new Person based on the old one but with the differences set on the expression
var otherPerson = person with { LastName = "Groupie" };