cdm/src/main/java/ucar/ma2/ArrayChar.java
@Override
  public ByteBuffer getDataAsByteBuffer() {
    ByteBuffer bb = ByteBuffer.allocate((int)getSize());
    resetLocalIterator();
    while (hasNext())
      bb.put( nextByte());
    return bb;
  }
@Override
  public ByteBuffer getDataAsByteBuffer() {
    ByteBuffer bb = ByteBuffer.allocate((int)getSize());
    resetLocalIterator();
    while (hasNext())
      bb.put( nextByte());
    return bb;
  }
Trasfer data to a ByteBuffer.
Note we cast char to byte, discarding top byte, if any.
This is because CDM char is really a byte, not a java char.
@return data in a ByteBuffer