void readWrite(SomethingHead head);

default byte[] saveToByteArray aka saveAsByteArray aka toByteArray() {
  var baos = byteArrayOutputStream();
  readWrite(new SomethingHead(baos));
  ret baos.toByteArray();
}

default File saveToFile(File file) {
  temp OutputStream out = bufferedFileOutputStream(file);
  readWrite(new SomethingHead(out));
  ret file;
}

default selfType load(byte[] data) {
  readWrite(new SomethingHead(new ByteArrayInputStream(data)));
  this;
}

default selfType load(File file) {
  temp InputStream in = bufferedInputStream(file);
  readWrite(new SomethingHead(in));
  this;
}