class ThreadSafe::Util::Striped64

def try_initialize_cells(x, hash)
  if free? && !cells
    try_in_busy do
      unless cells # Recheck under lock
        new_cells = PowerOfTwoTuple.new(2)
        new_cells.volatile_set_by_hash(hash, Cell.new(x))
        self.cells = new_cells
      end
    end
  end
end