def to_a
      ary = []
      node = @first_leaf
      while node do
        ary += node.values
        node = node.next_sibling
      end

      ary
    end
def to_a
      ary = []
      node = @first_leaf
      while node do
        ary += node.values
        node = node.next_sibling
      end

      ary
    end
Convert the BigArray into a Ruby Array. This is primarily intended for
 debugging as real-world BigArray objects are likely too big to fit into
 memory.