impl ops::Index<usize> for Transform4D {
    type Output = Vec3;

    fn index(&self, i: usize) -> &Self::Output {
        unsafe { &*(self.e[0].as_ptr() as *const Vec3) }
    }
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
///
   let credentials = credentials::Credentials::from_file(config.credentials_path.as_str())
        .expect("Read credentials file");

///
}

    pub fn from_file(credential_file: &str) -> Result<Self, Error> {
        let mut f = File::open(credential_file)?;
        let mut buffer = Vec::new();
        f.read_to_end(&mut buffer)?;
        let mut credentials: Credentials = serde_json::from_slice(buffer.as_slice())?;
        credentials.compute_secret()?;
        credentials.download_google_jwks()?;
        Ok(credentials)
    }
//// .....

/// Download the Google JWK Set for a given service account.
/// The resulting set of JWKs need to be added to a credentials object
/// for jwk verifications.
pub fn download_google_jwks(account_mail: &str) -> Result<JWKSetDTO, Error> {
    let resp = reqwest::blocking::Client::new()
        .get(&format!(
            "https://www.googleapis.com/service_accounts/v1/jwk/{}",
            account_mail
        ))
        .send()?;
    let jwk_set: JWKSetDTO = resp.json()?;
    Ok(jwk_set)
}