.NET 6 System.Text.Json.Nodes and System.Text.Json source generation, with top-level statements

Program.cs

using System.Diagnostics;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.Json.Serialization;

/*

Testing out .NET 6 JSON DOM for "late binding" of models to a document with unknown structure.
Also added source generation for JSON deserialization, both for the base model and the "late bound" model.

{
    "name": "Nick",
    "pets": [
        {
            "name": "Moon",
            "type": "Cat",
            "attributes": {
                "ownsTheHouse": true
            }
        },
        {
            "name": "Melody",
            "type": "Dog",
            "attributes": {
                "isAGoodDog": true
            }
        }
    ]
}
*/

var jsonString = "{\r\n    \"name\": \"Nick\",\r\n    \"pets\": [\r\n        {\r\n            \"name\": \"Moon\",\r\n            \"type\": \"Cat\",\r\n            \"attributes\": {\r\n                \"ownsTheHouse\": true\r\n            }\r\n        },\r\n        {\r\n            \"name\": \"Melody\",\r\n            \"type\": \"Dog\",\r\n            \"attributes\": {\r\n                \"isAGoodDog\": true\r\n            }\r\n        }\r\n    ]\r\n}";
var jsonOptions = new JsonSerializerOptions
{
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
};
jsonOptions.AddContext<PersonJsonContext>(); // represents our base model

var lateBoundOptions = new JsonSerializerOptions
{
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
};
lateBoundOptions.AddContext<MyJsonContext>(); // SDK consumers could provide as perf benefit

var stopwatch = new Stopwatch();
stopwatch.Start();

var person = JsonSerializer.Deserialize<Person>(jsonString, jsonOptions);
Console.WriteLine($"hello {person?.Name}");
foreach (var pet in person.Pets)
{
    Console.WriteLine($"hello {pet.Name} you {pet.Type}!");
    switch (pet.Type.ToLowerInvariant())
    {
        case "dog":
            Console.WriteLine($"Are you a good dog? {pet.Attributes["isAGoodDog"]}");
            var dog = pet.Attributes.Deserialize<Dog>(lateBoundOptions);
            if (dog.IsAGoodDog)
            {
                Console.WriteLine("You really are a good dog!");
            }
            break;
        case "cat":
            Console.WriteLine($"Does the kitty own the house? {pet.Attributes["ownsTheHouse"]}");
            var cat = pet.Attributes.Deserialize<Cat>(lateBoundOptions);
            if (cat.OwnsTheHouse)
            {
                Console.WriteLine("It's your house.");
            }
            break;
    }
}
stopwatch.Stop();
Console.WriteLine($"Done in {stopwatch.ElapsedMilliseconds}ms");

public class Person
{
    public string Name { get; set; }
    public Pet[] Pets { get; set; }
}

public class Pet
{
    public string Name { get; set; }
    public string Type { get; set;}

    public JsonObject Attributes { get; set; } 
}

public class Dog
{
    public bool IsAGoodDog { get; set;}
}

public class Cat
{
    public bool OwnsTheHouse { get; set; }
}

// Attempt to optimize deserialization
// https://devblogs.microsoft.com/dotnet/try-the-new-system-text-json-source-generator/
[JsonSerializable(typeof(Person), GenerationMode = JsonSourceGenerationMode.Metadata)]
internal partial class PersonJsonContext : JsonSerializerContext
{

}


// SDK consumers could create their own and provide to us as perf optimization
[JsonSerializable(typeof(Dog), GenerationMode = JsonSourceGenerationMode.Metadata)]
[JsonSerializable(typeof(Cat), GenerationMode = JsonSourceGenerationMode.Metadata)]
internal partial class MyJsonContext : JsonSerializerContext
{

}

/* OUTPUT

hello Nick
hello Moon you Cat!
Does the kitty own the house? true
It's your house.
hello Melody you Dog!
Are you a good dog? true
You really are a good dog!

*/