impl MetaConfig {
    pub fn default() -> Self {
        MetaConfig {
            meta_address: "".to_string(),
            meta_username: "root".to_string(),
            meta_password: "".to_string(),
            rpc_tls_meta_server_root_ca_cert: "".to_string(),
            rpc_tls_meta_service_domain_name: "localhost".to_string(),
        }
    }
}

impl MetaConfig {
    pub fn default() -> Self {
       <Self as StructOpt>::from_iter(&Vec::<&'static str>::new())
    }
}