def to_segment(sym)
      return nil unless EXPORT.include?(sym)

      seg = __send__(sym)
      return nil unless seg.is_a?(Segment)

      seg
    end
def to_segment(sym)
      return nil unless EXPORT.include?(sym)

      seg = __send__(sym)
      return nil unless seg.is_a?(Segment)

      seg
    end
Convert symbol to segment.

 @return [HeapInfo::Segment?]
   The segment object.