@Override
    public <T> CompletableFuture<T> newContextAwareFuture(RequestContext ctx) {
        return new Java9ContextAwareFuture<>(requireNonNull(ctx, "ctx"));
    }
Implementation of {@link JavaVersionSpecific} using Java 9 APIs.
core/src/main/java9/com/linecorp/armeria/internal/common/Java9VersionSpecific.java