# System.Text.Json.Serialization

``` diff
 namespace System.Text.Json.Serialization {
     public abstract class JsonConverter<T> : JsonConverter {
-        public virtual void WriteAsPropertyName(Utf8JsonWriter writer, T value, JsonSerializerOptions options);
+        public virtual void WriteAsPropertyName(Utf8JsonWriter writer, [DisallowNullAttribute] T value, JsonSerializerOptions options);
     }
 }
```

