pub fn keypair_opt_using(
signature_scheme: SignatureScheme,
encapsulation_scheme: EncapsulationScheme,
rng: &mut impl RandomNumberGenerator,
) -> Result<(PrivateKeys, PublicKeys)>pub fn keypair_opt_using(
signature_scheme: SignatureScheme,
encapsulation_scheme: EncapsulationScheme,
rng: &mut impl RandomNumberGenerator,
) -> Result<(PrivateKeys, PublicKeys)>