EWMA panics go1.1.2 linux/386 about go-metrics HOT 3 CLOSED

package main

import (
  "sync/atomic"
  "log"
)

type A struct {
  uncounted int64
}

type B struct {
  init      bool
  uncounted int64
}

func main() {
  a := &A{}
  b := &B{}
  var n int64 = 2

  atomic.AddInt64(&a.uncounted, n)
  log.Printf("a's count is %d", a.uncounted)

  atomic.AddInt64(&b.uncounted, n)
  log.Printf("b's count is %d", a.uncounted)

  log.Printf("All done!")
}