pub fn fn_hello_retry_extensions_append(
extensions: &Vec<HelloRetryExtension>,
extension: &HelloRetryExtension,
) -> Result<Vec<HelloRetryExtension>, FnError>pub fn fn_hello_retry_extensions_append(
extensions: &Vec<HelloRetryExtension>,
extension: &HelloRetryExtension,
) -> Result<Vec<HelloRetryExtension>, FnError>