src/main/java/io/reactivex/subjects/UnicastSubject.java
@CheckReturnValue
    @NonNull
    public static <T> UnicastSubject<T> create(boolean delayError) {
        return new UnicastSubject<T>(bufferSize(), delayError);
    }
@CheckReturnValue
    @NonNull
    public static <T> UnicastSubject<T> create(boolean delayError) {
        return new UnicastSubject<T>(bufferSize(), delayError);
    }
Creates an UnicastSubject with an internal buffer capacity hint 16 and given delay error flag.

<p>The callback, if not null, is called exactly once and
non-overlapped with any active replay.
<p>History: 2.0.8 - experimental
@param <T> the value type
@param delayError deliver pending onNext events before onError
@return an UnicastSubject instance
@since 2.2