<PackageReference Include="Newtonsoft.Json" Version="8.0.2" />

ValidationEventHandler

public sealed delegate ValidationEventHandler : MulticastDelegate

Represents the callback method that will handle JSON schema validation events and the ValidationEventArgs.

JSON Schema validation has been moved to its own package. See http://www.newtonsoft.com/jsonschema for more details.
public ValidationEventHandler(object object, IntPtr method)

public virtual IAsyncResult BeginInvoke(object sender, ValidationEventArgs e, AsyncCallback callback, object object)

public virtual void EndInvoke(IAsyncResult result)

public virtual void Invoke(object sender, ValidationEventArgs e)