MoreAboutRecordStructs.cs

using System;
using System.Text;

var p1 = new Point(1d, 2d);
// p1.X = 3d; // This does not work because readonly records are immutable
Console.WriteLine(p1);

// Note: At the time of writing, deconstruct can be compiled on sharplab.io, but cannot be executed.
//       If you want to run this code on sharplab.io, comment the following statement.
var (x, y) = p1; // Deconstruction works similar to record classes.

var p2 = p1 with { X = 4d }; // We can use the with keyword

// Readonly leads to an immutable struct
// Note that you can use the property: syntax to apply attributes
// or you can apply attributes to manually declared properties.
readonly record struct Point(double X, [property: JsonPropertyName("y")] double Y)
{
    // It is possible to manually declare property.
    [JsonPropertyName("x")]
    public double X { get; init; } = X;

    // Although PrintMembers is private, we can add a custom implementation.
    // C# considers the members as "matching" if signature matches.
    private bool PrintMembers(StringBuilder sb)
    {
        sb.Append($"X/Y = {X}/{Y}");
        return true;
    }
}

// Simulate use of System.Text.Json
[AttributeUsage(AttributeTargets.Property)]
public class JsonPropertyNameAttribute : Attribute
{
    public JsonPropertyNameAttribute(string name) { /* ... */ }
}