Using EC2 Instance Metadata
When you run code within an EC2 instance (or EKS, Lambda), AsyncAws is able to fetch Credentials from the Role attached to the instance.
When running a single application on the Server, this is the simplest way to grant permissions to the application. You have nothing to configure on the application, you only grant permissions on the Role attached to the instance.
AsyncAWS uses the IMDSv2 protocol to read instance metadata and fallback to the IMDSv1 protocol if it isn't supported.