private static boolean checkPublicAccess(BlobStore blobStore,
            String containerName, String blobName) {
        String blobStoreType = getBlobStoreType(blobStore);
        if (Quirks.NO_BLOB_ACCESS_CONTROL.contains(blobStoreType)) {
            ContainerAccess access = blobStore.getContainerAccess(
                    containerName);
            return access == ContainerAccess.PUBLIC_READ;
        } else {
            BlobAccess access = blobStore.getBlobAccess(containerName,
                    blobName);
            return access == BlobAccess.PUBLIC_READ;
        }
    }
S3 supports arbitrary keys for the marker while some blobstores only
support opaque markers.  Emulate the common case for these by mapping
the last key from a listing to the corresponding previously returned
marker.
src/main/java/org/gaul/s3proxy/S3ProxyHandler.java