src/main/java/io/reactivex/Completable.java
@CheckReturnValue
    @SuppressWarnings("unchecked")
    @BackpressureSupport(BackpressureKind.FULL)
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <T> Flowable<T> toFlowable() {
        if (this instanceof FuseToFlowable) {
            return ((FuseToFlowable<T>)this).fuseToFlowable();
        }
        return RxJavaPlugins.onAssembly(new CompletableToFlowable<T>(this));
    }
@CheckReturnValue
    @SuppressWarnings("unchecked")
    @BackpressureSupport(BackpressureKind.FULL)
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <T> Flowable<T> toFlowable() {
        if (this instanceof FuseToFlowable) {
            return ((FuseToFlowable<T>)this).fuseToFlowable();
        }
        return RxJavaPlugins.onAssembly(new CompletableToFlowable<T>(this));
    }
Returns a Flowable which when subscribed to subscribes to this Completable and
relays the terminal events to the subscriber.
<p>
<img width="640" height="585" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.toFlowable.png" alt="">
<dl>
<dt><b>Backpressure:</b></dt>
<dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
<dt><b>Scheduler:</b></dt>
<dd>{@code toFlowable} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
@param <T> the value type
@return the new Flowable instance