default CompletableFuture<Void> shutdown() {
        return UnmodifiableFuture.completedFuture(null);
    }
Shuts down this {@link AccessLogWriter}.

@return the {@link CompletableFuture} which is completed
        when this {@link AccessLogWriter} has been shut down.
core/src/main/java/com/linecorp/armeria/server/logging/AccessLogWriter.java