T - the type of element signaled.public interface Publisher<T>
Publisher is a provider of a potentially unbounded number of sequenced elements, publishing them according to
 the demand received from its Subscriber(s).
 
 A Publisher can serve multiple Subscribers subscribed subscribe(Subscriber) dynamically
 at various points in time.
| Modifier and Type | Method and Description | 
|---|---|
void | 
subscribe(Subscriber<? super T> s)
Request  
Publisher to start streaming data. | 
void subscribe(Subscriber<? super T> s)
Publisher to start streaming data.
 
 This is a "factory method" and can be called multiple times, each time starting a new Subscription.
 
 Each Subscription will work for only a single Subscriber.
 
 A Subscriber should only subscribe once to a single Publisher.
 
 If the Publisher rejects the subscription attempt or otherwise fails it will
 signal the error via Subscriber.onError(java.lang.Throwable).
s - the Subscriber that will consume signals from this Publisher