aws-sdk/lib/config_use_dualstack.d.ts

export interface UseDualstackConfigOptions {
    /**
     * Enables IPv6/IPv4 dualstack endpoint. When a DNS lookup is performed on an endpoint of this type, it returns an “A” record with an IPv4 address and an “AAAA” record with an IPv6 address. 
     * In most cases the network stack in the client environment will automatically prefer the AAAA record and make a connection using the IPv6 address. 
     * Note, however, that currently on Windows, the IPv4 address will be preferred.
     */
    useDualstack?: boolean;
}