pub fn fn_rsa_sign_client(
transcript: &HandshakeHash,
private_key: &Vec<u8>,
scheme: &SignatureScheme,
) -> Result<Vec<u8>, FnError>pub fn fn_rsa_sign_client(
transcript: &HandshakeHash,
private_key: &Vec<u8>,
scheme: &SignatureScheme,
) -> Result<Vec<u8>, FnError>