@Override
    public int processBytes(byte[] in, int inOff, int len, byte[] out, int outOff) throws DataLengthException {
        return cipher.processBytes(in, inOff, len, out, outOff);
    }
Minimal adapter to make ChaCha20Poly1305 usable as an AEADBlockCipher (it's technically
an AEAD stream cipher, but this is not exposed in the BouncyCastle type system).

@author vekterli
security-utils/src/main/java/com/yahoo/security/ChaCha20Poly1305AeadBlockCipherAdapter.java