According to AWS documentation there is a possibility to launch AWS either using Multi-AZ DB Instance deployment (1 Standby Instance) or Multi-AZ DB Cluster deployment (2 standby Instances) according to this page: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html
But in Terraform AWS Provider documentation page (https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/db_instance) I see multi_az argument which allows the creation of DB Instance with 1 standby Instance, but I don't know how to have 2 standby Instances. Also, there is aws_rds_cluster resource, but it is intended for Amazon Aurora as I understand from documentation.
What should be provided arguments into aws_db_instance resource to have Multi-AZ deployment with 2 standby Instances ?