namespace System.Text.Json
{
    public ref partial struct Utf8JsonReader
    {
+        public BigInteger GetBigInteger();
+        public bool TryGetBigInteger(out BigInteger value);
    }

    public sealed partial class Utf8JsonWriter
    {
+        public void WriteNumber(JsonEncodedText propertyName, BigInteger value);
+        public void WriteNumber(string propertyName, BigInteger value);
+        public void WriteNumber(ReadOnlySpan<char> propertyName, BigInteger value);
+        public void WriteNumber(ReadOnlySpan<byte> utf8PropertyName, BigInteger value);
+        public void WriteNumberValue(BigInteger value);
    }

    public readonly partial struct JsonElement
    {
+        public BigInteger GetBigInteger();
+        public bool TryGetBigInteger(out BigInteger value)
    }
}

namespace System.Text.Json.Node
{
    public abstract partial class JsonNode
    {
+        public static explicit operator BigInteger(JsonNode value);
+        public static explicit operator BigInteger?(JsonNode? value);
+        public static implicit operator JsonNode(BigInteger value);
+        public static implicit operator JsonNode?(BigInteger? value);
    }
}

namespace System.Text.Json.Serialization.Metadata
{
    public static partial class JsonMetadataServices
    {
+        public static JsonConverter<BigInteger> BigIntegerConverter { get; }
    }
}

JsonSerializer.Serialize((BigInteger)42);

// Current JSON: {"IsPowerOfTwo":false,"IsZero":false,"IsOne":false,"IsEven":true,"Sign":1}
// New JSON: 42