src/main/java/io/reactivex/Flowable.java
@CheckReturnValue
    @NonNull
    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <U> Flowable<T> takeUntil(Publisher<U> other) {
        ObjectHelper.requireNonNull(other, "other is null");
        return RxJavaPlugins.onAssembly(new FlowableTakeUntil<T, U>(this, other));
    }
@CheckReturnValue
    @NonNull
    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <U> Flowable<T> takeUntil(Publisher<U> other) {
        ObjectHelper.requireNonNull(other, "other is null");
        return RxJavaPlugins.onAssembly(new FlowableTakeUntil<T, U>(this, other));
    }
@ CheckReturnValue @ NonNull @ BackpressureSupport ( BackpressureKind . PASS_THROUGH ) @ SchedulerSupport ( SchedulerSupport . NONE ) public final < U > Flowable < T > takeUntil ( Publisher < U > other ) { ObjectHelper . requireNonNull ( other , "other is null" ) ; return RxJavaPlugins . onAssembly ( new FlowableTakeUntil < T , U > ( this , other ) ) ; }
Returns a Flowable that emits the items emitted by the source Publisher until a second Publisher
emits an item.
<p>
<img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/takeUntil.png" alt="">
<dl>
<dt><b>Backpressure:</b></dt>
<dd>The operator doesn't interfere with backpressure which is determined by the source {@code Publisher}'s backpressure
behavior.</dd>
<dt><b>Scheduler:</b></dt>
<dd>{@code takeUntil} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param other
the Publisher whose first emitted item will cause {@code takeUntil} to stop emitting items
from the source Publisher
@param <U>
the type of items emitted by {@code other}
@return a Flowable that emits the items emitted by the source Publisher until such time as {@code other} emits its first item
@see <a href="http://reactivex.io/documentation/operators/takeuntil.html">ReactiveX operators documentation: TakeUntil</a>
Returns a Flowable that emits the items emitted by the source Publisher until a second Publisher emits an item . <p > <img width = 640 height = 380 src = https : // raw . github . com / wiki / ReactiveX / RxJava / images / rx - operators / takeUntil . png alt = > <dl > <dt > <b > Backpressure : < / b > < / dt > <dd > The operator doesn t interfere with backpressure which is determined by the source { @code Publisher } s backpressure behavior . < / dd > <dt > <b > Scheduler : < / b > < / dt > <dd > { @code takeUntil } does not operate by default on a particular { @link Scheduler } . < / dd > < / dl >