<PackageReference Include="System.Data.SqlClient" Version="4.7.0-rc1.19456.4" />

OnChangeEventHandler

public sealed delegate OnChangeEventHandler : MulticastDelegate
Handles the OnChange event that is fired when a notification is received for any of the commands associated with a SqlDependency object.
public OnChangeEventHandler(object object, IntPtr method)

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

public virtual void EndInvoke(IAsyncResult result)

public virtual void Invoke(object sender, SqlNotificationEventArgs e)