static byte[] toByteArray(ByteArrayOutputStream baos) {

  ret baos == null ? null : baos.toByteArray();

}

static byte[] toByteArray(Iterator<? extends Number> it) {

  new ByteBuffer buf;

  while (it.hasNext())

    buf.add((byte) it.next().intValue());

  ret buf.toByteArray();

}

static byte[] toByteArray(Cl<? extends Number> it) {

  int n = l(it), i = 0;

  byte[] a = new[n];

  for (x : it)

    a[i++] = (byte) x.intValue();

  ret a;

}

static byte[] toByteArray(O o) {

  if (o == null) null;

  if (o cast byte[]) ret o;

  if (o instanceof Iterator)

    ret toByteArray((Iterator<Number>) o);

  if (o cast Cl)

    ret toByteArray((Cl<Number>) o);

  // not sure what else to put here

  fail("toByteArray", o);

}

// Note: Does not rewind the buffer

static byte[] toByteArray(java.nio.ByteBuffer buf) {

  if (buf == null) null;

  byte[] a = new[buf.remaining()];

  buf.get(a);

  ret a;

}