@Override
        public void subscribe(CoreSubscriber<? super Object> subscriber) {
            try (SafeCloseable ignored = ctx.push()) {
                if (subscriber instanceof ContextAwareCoreSubscriber) {
                    source.subscribe(subscriber);
                } else {
                    source.subscribe(new ContextAwareCoreSubscriber(subscriber, ctx));
                }
            }
        }
Returns whether the specified {@link Publisher} is reproducible {@link Fuseable.ScalarCallable} such as
{@link Flux#empty()}, {@link Flux#just(Object)}, {@link Flux#error(Throwable)},
{@link Mono#empty()}, {@link Mono#just(Object)} and {@link Mono#error(Throwable)}.
reactor3/src/main/java/com/linecorp/armeria/common/reactor3/RequestContextHooks.java