NServiceBus using type attributes in unobtrusive mode

conventions.cs

// Usage: endpointConfiguration.Conventions().Apply();

[AttributeUsage(AttributeTargets.Class|AttributeTargets.Interface)]
public class MessageAttribute : Attribute
{
}

[AttributeUsage(AttributeTargets.Class|AttributeTargets.Interface)]
public sealed class EventAttribute : MessageAttribute
{
}

[AttributeUsage(AttributeTargets.Class|AttributeTargets.Interface)]
public sealed class CommandAttribute : MessageAttribute
{
}

[AttributeUsage(AttributeTargets.Property)]
public sealed class DataBusPropertyAttribute : MessageAttribute
{
}
    
public static class Conventions
{
    static bool IsMessage(Type t) => t != null && t.IsDefined(typeof(MessageAttribute), true);
    static bool IsEvent(Type t) => t != null && t.IsDefined(typeof(EventAttribute), true);
    static bool IsCommand(Type t) => t != null && t.IsDefined(typeof(CommandAttribute), true);
    static bool IsDataBusProperty(PropertyInfo pi) => pi != null && Attribute.IsDefined(pi, typeof(DataBusPropertyAttribute));

    public static void Apply(this ConventionsBuilder instance)
    {
        instance.DefiningEventsAs(IsEvent);
        instance.DefiningCommandsAs(IsCommand);
        instance.DefiningMessagesAs(IsMessage);
        instance.DefiningDataBusPropertiesAs(IsDataBusProperty);
    }
}