@Override
    protected byte[] engineGenerateSeed(int numBytes) {
        byte[] output = new byte[numBytes];
        NativeCrypto.RAND_bytes(output);
        return output;
    }
Implements {@link java.security.SecureRandom} using BoringSSL's RAND interface.
common/src/main/java/org/conscrypt/OpenSSLRandom.java