The pulumi AI insists that the following is valid:

// Create a custom VPC
const vpc = new awsx.ec2.Vpc("customVPC", { numberOfAvailabilityZones: 2 });

// Create an ECS cluster in the custom VPC
const cluster = new awsx.ecs.Cluster("cluster", { vpc });

The only thing is that it is not supported, and I can't get Pulumi AI to not do it.