// files. Internally, the tar format often uses fake "files" to add meta
	// data that describes the next file. These meta data "files" should not
	// normally be visible to the outside. As such, this loop iterates through
	// one or more "header files" until it finds a "normal file".
	format := FormatUSTAR | FormatPAX | FormatGNU
	for {
		// Discard the remainder of the file and any padding.

	}
	if err := writer.Close(); err != nil {
		t.Fatal(err)
	}
	// Simple test to make sure PAX extensions are in effect
	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.0")) {
		t.Fatal("Expected at least one PAX header to be written.")
	}
	// Test that we can get a long name back out of the archive.
	reader := NewReader(&buf)
	hdr, err = reader.Next()
	if err != nil {
		t.Fatal(err)
	}
	if hdr.Name != longName {

	}

	return w.writeDataDescriptor()
}

func (w *fileWriter) writeDataDescriptor() error {
	if !w.hasDataDescriptor() {
		return nil
	}
	// Write data descriptor. This is more complicated than one would
	// think, see e.g. comments in zipfile.c:putextended() and
	// https://bugs.openjdk.org/browse/JDK-7073588.
	// The approach here is to write 8 byte sizes if needed without