code: @Override
    public void readHeader(RandomAccessFile file) throws IOException {
      super.readHeader(file);
      this.min_fanout = file.readInt();
      this.num_elements = file.readLong();
      this.dimensionality = file.readInt();
      this.max_overlap = file.readFloat();
      this.supernode_offset = file.readLong();
    }
docs: Initializes this header from the specified file. Reads the integer values
  <code>version</code>, <code>pageSize</code>, {@link #dirCapacity},
  {@link #leafCapacity}, {@link #dirMinimum}, and {@link #leafMinimum}, as
  well as the minimum fanout {@link #min_fanout}, the tree's dimension
  {@link #dimensionality}, the maximum overlap
  {@link #max_overlap} and the supernode offset {@link #supernode_offset}
  from the file.