问如何在RxJs 5中将项目分组为大小为n的组？

EN

Observable.create(observer => {
    setTimeout(() => observer.next([1]),            90)
    setTimeout(() => observer.next([2, 3]),        120)
    setTimeout(() => observer.next([4, 5, 6]),     160)
    setTimeout(() => observer.next([7, 8, 9, 10]), 310)
    setTimeout(() => observer.next([11]),          360)
})
.flatMap(xs => xs)
.bufferTime(100, 100, 3) // group every 100 ms or by 3, whatever comes first
.takeUntil(Observable.timer(590))
.subscribe(x => console.log(x))

[ 1 ]
[ 2, 3, 4 ]
[]
[ 7, 8, 9 ]
[ 11 ]
[]

[ 1 ]
[ 2, 3, 4 ]
[ 5, 6 ]
[]
[ 7, 8, 9 ]
[ 10, 11 ]
[]