src/main/java/io/reactivex/Flowable.java
@CheckReturnValue
    @NonNull
    @BackpressureSupport(BackpressureKind.FULL)
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Single<Boolean> sequenceEqual(Publisher<? extends T> source1, Publisher<? extends T> source2,
            BiPredicate<? super T, ? super T> isEqual, int bufferSize) {
        ObjectHelper.requireNonNull(source1, "source1 is null");
        ObjectHelper.requireNonNull(source2, "source2 is null");
        ObjectHelper.requireNonNull(isEqual, "isEqual is null");
        ObjectHelper.verifyPositive(bufferSize, "bufferSize");
        return RxJavaPlugins.onAssembly(new FlowableSequenceEqualSingle<T>(source1, source2, isEqual, bufferSize));
    }
@CheckReturnValue
    @NonNull
    @BackpressureSupport(BackpressureKind.FULL)
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Single<Boolean> sequenceEqual(Publisher<? extends T> source1, Publisher<? extends T> source2,
            BiPredicate<? super T, ? super T> isEqual, int bufferSize) {
        ObjectHelper.requireNonNull(source1, "source1 is null");
        ObjectHelper.requireNonNull(source2, "source2 is null");
        ObjectHelper.requireNonNull(isEqual, "isEqual is null");
        ObjectHelper.verifyPositive(bufferSize, "bufferSize");
        return RxJavaPlugins.onAssembly(new FlowableSequenceEqualSingle<T>(source1, source2, isEqual, bufferSize));
    }
Returns a Single that emits a Boolean value that indicates whether two Publisher sequences are the
same by comparing the items emitted by each Publisher pairwise based on the results of a specified
equality function.
<p>
<img width="640" height="385" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sequenceEqual.png" alt="">
<dl>
<dt><b>Backpressure:</b></dt>
<dd>The operator honors backpressure from downstream. The source {@code Publisher}s are expected to honor
backpressure; if violated, the operator signals a {@code MissingBackpressureException}.</dd>
<dt><b>Scheduler:</b></dt>
<dd>{@code sequenceEqual} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param source1
the first Publisher to compare
@param source2
the second Publisher to compare
@param isEqual
a function used to compare items emitted by each Publisher
@param bufferSize
the number of items to prefetch from the first and second source Publisher
@param <T>
the type of items emitted by each Publisher
@return a Single that emits a Boolean value that indicates whether the two Publisher sequences
are the same according to the specified function
@see <a href="http://reactivex.io/documentation/operators/sequenceequal.html">ReactiveX operators documentation: SequenceEqual</a>