pairwise method
Emits the n-th and n-1th events as a pair. The first event won't be emitted until the second one arrives.
Example
RangeStream(1, 4)
.pairwise()
.listen(print); // prints [1, 2], [2, 3], [3, 4]
Implementation
Stream<List<T>> pairwise() => PairwiseStreamTransformer<T>().bind(this);