monoandroid 
namespace System.Text.Json.Serialization
{
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
    public sealed class JsonSourceGenerationOptionsAttribute : JsonAttribute
    {
        public bool InferClosedTypePolymorphism { get; set; }
    }
}
Design Reviews
.NET
5.06.07.08.09.010.011.0
.NET Core
2.02.12.23.03.1
.NET Framework
4.6.14.6.24.74.7.14.7.24.84.8.1
.NET Standard
2.02.1
Information specific to monoandroid
Assembly

System.Text.Json , Version=11.0.0.0, PublicKeyToken=cc7b13ffcd2ddd51

Referencing

Your project needs a package reference to System.Text.Json.

Package System.Text.Json (11.0.0-rc.2.26504.105) netstandard2.0
Preview This API is contained in a prerelease package.
Platform Restrictions

This framework does not have platform annotations.

  • Built-in API
  • Package-provided API