/**
* Create a default credential provider that first checks for environment
* variables, then checks for the "default" profile in ~/.aws/credentials,
* and finally checks for credentials using EC2 instance profile
* credentials.
*
* @param array $config Optional array of instance profile credentials
* provider options.
* @return callable
*/
public static function defaultProvider(array $config = [])
{
return Utils::orFn(self::env(), self::ini(), self::instanceProfile($config));
}
