@Override
    public final CompletableFuture<Boolean> canList(Executor fileReadExecutor, String path) {
        requireNonNull(fileReadExecutor, "fileReadExecutor");
        requireNonNull(path, "path");

        if (directoryListingSupported) {
            return CompletableFuture.supplyAsync(() -> blockingCanList(fileReadExecutor, path),
                                                 fileReadExecutor);
        } else {
            return super.canList(fileReadExecutor, path);
        }
    }
{@inheritDoc} This method invokes {@link #blockingCanList(Executor, String)} from the specified
{@code fileReadExecutor}.
core/src/main/java/com/linecorp/armeria/server/file/AbstractBlockingHttpVfs.java