code: public static <E> UnicastProcessor<E> create(Queue<E> queue,
  			Consumer<? super E> onOverflow,
  			Disposable endcallback) {
  		return new UnicastProcessor<>(queue, onOverflow, endcallback);
  	}
docs: Create a new {@link UnicastProcessor} that will buffer on a provided queue in an
  unbounded fashion.
  
  @param queue the buffering queue
  @param endcallback called on any terminal signal
  @param onOverflow called when queue.offer return false and unicastProcessor is
  about to emit onError.
  @param <E> the relayed type
  
  @return a unicast {@link FluxProcessor}