@Override
    public MultipartPart uploadMultipartPart(MultipartUpload mpu,
            int partNumber, Payload payload) {
        MultipartPart part = delegate().uploadMultipartPart(mpu, partNumber,
                payload);
        return part;
    }
This class is a BlobStore wrapper which emulates eventual consistency
using two blobstores.  It writes objects to one store and reads objects
from another.  An asynchronous process copies objects between stores.  Note
that container operations are not eventually consistent.
src/main/java/org/gaul/s3proxy/EventualBlobStore.java