public void init(PublicKey recipientKey, byte[] info) throws InvalidKeyException {
        spi.engineInitSender(
                recipientKey, info, null, HpkeSpi.DEFAULT_PSK, HpkeSpi.DEFAULT_PSK_ID);
    }
Initialises this HpkeContextSender in BASE mode, i.e. with no sender authentication.

@param recipientKey public key of the recipient
@param info additional application-supplied information, may be null or empty
@throws InvalidKeyException if recipientKey is null or an unsupported key format
@throws UnsupportedOperationException if mode is not a supported HPKE mode
@throws IllegalStateException if this HpkeContextSender has already been initialised
common/src/main/java/org/conscrypt/HpkeContextSender.java