Hey I'm working on an app that uses Paho mqtt

Now I'm trying to cast the contents of a couple of objects to byte arrays so I can send them to the broker. There are a couple of different objects that all adhere to a abstract class, but the one I started with contains a double[]

Here's the function I'm trying to implement:

```
    @Override
public byte[] getBytes() {

    return Arrays.stream(driveVector).map(d -> Double.valueOf(d).byteValue()).toArray();
}

```

I thought this would work, but I get an error that the return value is a double[]

I think I either don't understand the map method or I'm goin about this all wrong in general (I looked at the ByteBuffer class, but it seems like a pain to implement this with it)

Thanks in advance