func (c *ec2MetadataClientImpl) DefaultCredentials() (*RoleCredentials, error) {
	securityCredential, err := c.client.GetMetadata(SecurityCrednetialsResource)
	if err != nil {
		return nil, err
	}

	securityCredentialList := strings.Split(strings.TrimSpace(securityCredential), "\n")
	if len(securityCredentialList) == 0 {
		return nil, errors.New("No security credentials in response")
	}

	defaultCredentialName := securityCredentialList[0]

	defaultCredentialStr, err := c.client.GetMetadata(SecurityCrednetialsResource + defaultCredentialName)
	if err != nil {
		return nil, err
	}
	var credential RoleCredentials
	err = json.Unmarshal([]byte(defaultCredentialStr), &credential)
	if err != nil {
		return nil, err
	}
	return &credential, nil
}
func (c *ec2MetadataClientImpl) DefaultCredentials() (*RoleCredentials, error) {
	securityCredential, err := c.client.GetMetadata(SecurityCrednetialsResource)
	if err != nil {
		return nil, err
	}

	securityCredentialList := strings.Split(strings.TrimSpace(securityCredential), "\n")
	if len(securityCredentialList) == 0 {
		return nil, errors.New("No security credentials in response")
	}

	defaultCredentialName := securityCredentialList[0]

	defaultCredentialStr, err := c.client.GetMetadata(SecurityCrednetialsResource + defaultCredentialName)
	if err != nil {
		return nil, err
	}
	var credential RoleCredentials
	err = json.Unmarshal([]byte(defaultCredentialStr), &credential)
	if err != nil {
		return nil, err
	}
	return &credential, nil
}
// DefaultCredentials returns the credentials associated with the instance iam role