spawn: how to get flowvar from flowvarbase?

[shirleyquirk]

if `'^'` wants a FlowVar, give it a FlowVar 
    
    
    proc spawn_collatz_p(cpu:int, ub:uint64):seq[(uint64,int)] =
      var responses:seq[FlowVar[seq[(uint64,uint64)]]]
      responses.setLen(cpu)
      parallel:
        for i in 0..<cpu:
          responses[i] = spawn list_collatz(uint64(i + 1), ub, cpu.uint64)
      for i in 0..<cpu:
        result = result & ^responses[i]
    
    
    Run