dotnet-core/release-notes/3.0/preview/api-diff/preview6/3.0-preview6_System.Text.Json.Serialization.md

System.Text.Json.Serialization

 namespace System.Text.Json.Serialization {
+    public sealed class JsonExtensionDataAttribute : JsonAttribute {
+        public JsonExtensionDataAttribute();
+    }
     public sealed class JsonPropertyNameAttribute : JsonAttribute {
-        public JsonPropertyNameAttribute(string propertyName);
+        public JsonPropertyNameAttribute(string name);
-        public string Name { get; set; }
+        public string Name { get; }
     }
     public static class JsonSerializer {
+        public static object ReadValue(ref Utf8JsonReader reader, Type returnType, JsonSerializerOptions options = null);
+        public static TValue ReadValue<TValue>(ref Utf8JsonReader reader, JsonSerializerOptions options = null);
-        public static byte[] ToBytes(object value, Type type, JsonSerializerOptions options = null);

-        public static byte[] ToBytes<TValue>(TValue value, JsonSerializerOptions options = null);

+        public static byte[] ToUtf8Bytes(object value, Type type, JsonSerializerOptions options = null);
+        public static byte[] ToUtf8Bytes<TValue>(TValue value, JsonSerializerOptions options = null);
     }
 }