code: func (t *table) appendTags() {
  	for j := range t.cols {
  		v := t.tags[j]
  		if v != nil {
  			b := arrow.NewStringBuilder(&memory.Allocator{})
  			b.Reserve(t.l)
  			for i := 0; i < t.l; i++ {
  				b.Append(v)
  			}
  			t.colBufs[j] = b.NewArray()
  			b.Release()
  		}
  	}
  }
docs: // appendTags fills the colBufs for the tag columns with the tag value.