* @throws IOException
*/
public void deserialize(DataTree dt, Map<Long, Long> sessions,
InputArchive ia) throws IOException {
FileHeader header = new FileHeader();
header.deserialize(ia, "fileheader");
if (header.getMagic() != SNAP_MAGIC) {
throw new IOException("mismatching magic headers "
+ header.getMagic() +
" != " + FileSnap.SNAP_MAGIC);
}