src/main/java/io/reactivex/Notification.java
@NonNull
    public static <T> Notification<T> createOnNext(@NonNull T value) {
        ObjectHelper.requireNonNull(value, "value is null");
        return new Notification<T>(value);
    }
@NonNull
    public static <T> Notification<T> createOnNext(@NonNull T value) {
        ObjectHelper.requireNonNull(value, "value is null");
        return new Notification<T>(value);
    }
Constructs an onNext notification containing the given value.
@param <T> the value type
@param value the value to carry around in the notification, not null
@return the new Notification instance
@throws NullPointerException if value is null