public async Task<IReadOnlyList<RealmInfo>> GetRealmsAsync(GetRealmsOptions? options = null)
{
    options ??= new();

    options.Context = context;

    return (await scriptModule.GetRealmsAsync(options).ConfigureAwait(false)).Realms;
}

        // https://github.com/dotnet/runtime/issues/72604
        new Json.Converters.Polymorphic.EvaluateResultConverter(),
        new Json.Converters.Polymorphic.RemoteValueConverter(),
        new Json.Converters.Polymorphic.RealmInfoConverter(),
        new Json.Converters.Polymorphic.LogEntryConverter(),
        //

        // Enumerable
        new Json.Converters.Enumerable.InputSourceActionsConverter(),
    }
};

_jsonSerializerContext = new BiDiJsonSerializerContext(jsonSerializerOptions);

public sealed class GetCookiesOptions : CommandOptions
{
    public CookieFilter? Filter { get; set; }

    public PartitionDescriptor? Partition { get; set; }
}

public sealed record GetCookiesResult(IReadOnlyList<Network.Cookie> Cookies, PartitionKey PartitionKey) : EmptyResult;

public sealed record CookieFilter
{
    public string? Name { get; set; }

// In Broker.cs
new JsonSerializerOptions
{
    Converters = 
    {
        // ...
        new Json.Converters.Enumerable.GetTreeResultConverter(),
        // ...
    }
};

// In GetTreeCommand.cs
public sealed record GetTreeResult : EmptyResult, IReadOnlyList<BrowsingContextInfo>
{
    // ... manual implementation ...
}

// In Broker.cs
new JsonSerializerOptions
{
    Converters = 
    {
        // GetTreeResultConverter is removed
    }
};

// In GetTreeCommand.cs, to be robust against serializer settings:
using System.Text.Json.Serialization;
public sealed record GetTreeResult(
    [property: JsonPropertyName("contexts")] IReadOnlyList<BrowsingContextInfo> Contexts
) : EmptyResult;