Rx.Observable.prototype.manySelect(selector, [scheduler]), Rx.Observable.prototype.extend(selector, [scheduler])

Comonadic bind operator.
参数
selector(Function): A transform function to apply to each element.[scheduler=Rx.Scheduler.immediate](Scheduler): Scheduler used to execute the operation. If not specified, defaults to theRx.Scheduler.immediatescheduler.
返回值
(Observable): An observable sequence which results from the comonadic bind operation.