@Override
    public CompletableFuture<AggregatedMultipart> aggregateWithPooledObjects(EventExecutor executor,
                                                                             ByteBufAllocator alloc) {
        requireNonNull(executor, "executor");
        requireNonNull(alloc, "alloc");
        return aggregate0(executor, alloc);
    }
Returns a random boundary used for encoding multipart messages.
core/src/main/java/com/linecorp/armeria/common/multipart/DefaultMultipart.java