src/main/java/io/reactivex/Single.java
@Experimental
    @CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Single<Notification<T>> materialize() {
        return RxJavaPlugins.onAssembly(new SingleMaterialize<T>(this));
    }
@Experimental
    @CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Single<Notification<T>> materialize() {
        return RxJavaPlugins.onAssembly(new SingleMaterialize<T>(this));
    }
Maps the signal types of this Single into a {@link Notification} of the same kind
and emits it as a single success value to downstream.
<p>
<img width="640" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/materialize.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code materialize} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
@return the new Single instance
@since 2.2.4 - experimental
@see #dematerialize(Function)