@Override
        public CompletableFuture<RequestLog> whenComplete() {
            if (completedFuture == null) {
                completedFuture = UnmodifiableFuture.completedFuture(this);
            }
            return completedFuture;
        }
A {@link RequestLog} that delegates to {@link DefaultRequestLog} to read properties without
checking availability.
core/src/main/java/com/linecorp/armeria/common/logging/DefaultRequestLog.java