src/main/java/io/reactivex/subjects/UnicastSubject.java
@CheckReturnValue
    @NonNull
    public static <T> UnicastSubject<T> create() {
        return new UnicastSubject<T>(bufferSize(), true);
    }
@CheckReturnValue
    @NonNull
    public static <T> UnicastSubject<T> create() {
        return new UnicastSubject<T>(bufferSize(), true);
    }
Creates an UnicastSubject with an internal buffer capacity hint 16.
@param <T> the value type
@return an UnicastSubject instance