How do I add a schema directive?

[willmarriott]

I'm looking to add a schema directive but having trouble working out how.
I've been able to add it to the Query via a QueryType.

[DirectiveType(DirectiveLocation.Object)]
public record MyDirective(string Name, string Value);

public QueryType : ObjectType<Query>
{
    protected override void Configure(IObjectTypeDescriptor<Query> descriptor)
    {
        descriptor.Directive(new MyDirective("name", "value"));
    }
}

var schema = await new ServiceCollection()
    .AddGraphQLServer()
    .AddQueryType<QueryType>()
    .BuildSchemaAsync();

How can I move this up to the schema?

[michaelstaib]

builder.Services
    .AddGraphQLServer()
    .AddTypes()
    .SetSchema(c => c.Directive(...));

[willmarriott]

Thank you @michaelstaib :)