code: func (e *LimitExec) Exec() *flow.Dataset {
  	d := e.Src.Exec()
  
  	k := int(e.Count + e.Offset)
  
  	ret := d.LocalLimit("limit", k, 0)
  	if len(d.Shards) > 1 {
  		ret = ret.MergeTo("merge", 1)
  	}
  	ret = ret.LocalLimit("limit", int(e.Count), int(e.Offset))
  	return ret
  }
docs: // Next implements the Executor Next interface.