Embed providerId into blobKey within KeyValueBlobTransientStore.putBlobs()

    @Override
    public void putBlobs(String key, List<Blob> blobs) {
        if (absoluteMaxSize > 0 && getStorageSize() > absoluteMaxSize) {
            // do the costly computation of the exact storage size if needed
            doGC();
            if (getStorageSize() > absoluteMaxSize) {
                throw new MaximumTransientSpaceExceeded();
            }
        }

        // remove previous blobs
        removeBlobs(key);

        KeyValueStore kvs = getKeyValueStore();
        BlobProvider bp = getBlobProvider();
        long totalSize = 0;
        int i = 0;
        for (Blob blob : blobs) {
            long size = blob.getLength();
            if (size >= 0) {
                totalSize += size;
            }
            // store blob
            String blobKey;
            try {
                blobKey = bp.writeBlob(blob);
            } catch (IOException e) {
                throw new NuxeoException(e);
            }
            int colon = blobKey.indexOf(':');
            String digest = (colon >= 0) ? blobKey.substring(colon + 1) : blobKey;
            blobKey = name + ":" + digest;
            // write blob data
            Map<String, String> blobMap = new HashMap<>();
            blobMap.put(KEY, blobKey);
            blobMap.put(MIMETYPE, blob.getMimeType());
            blobMap.put(ENCODING, blob.getEncoding());
            blobMap.put(FILENAME, blob.getFilename());
            blobMap.put(LENGTH, String.valueOf(size));
            blobMap.put(DIGEST, digest);
            kvs.put(key + DOT_BLOB_DOT + i, toJson(blobMap), ttl);
            i++;
        }
        Map<String, String> blobInfoMap = new HashMap<>();
        blobInfoMap.put(COUNT, String.valueOf(blobs.size()));
        blobInfoMap.put(SIZE, String.valueOf(totalSize));
        kvs.put(key + DOT_BLOBINFO, toJson(blobInfoMap), ttl);
        addStorageSize(totalSize);
        markEntryExists(key);
    }

    @Override
    public String writeBlob(Blob blob) throws IOException {
        // writes the blob and return its blobKey
        Binary binary = binaryManager.getBinary(blob);
        String digest = binary.getDigest();
        return binary.getProviderId() + ":" + digest;
    }

    @Override
    public Blob readBlob(BlobInfo blobInfo) throws IOException {
        String digest = blobInfo.key;
        // strip prefix
        int colon = digest.indexOf(':');
        if (colon >= 0) {
            digest = digest.substring(colon + 1);
        }
        Binary binary = binaryManager.getBinary(digest);
        if (binary == null) {
            throw new IOException("Unknown binary: " + digest);
        }
        String blobKey = binary.getProviderId() + ":" + digest;
        long length;
        if (blobInfo.length == null) {
            log.debug("Missing blob length for: " + blobInfo.key);
            // to avoid crashing, get the length from the binary's file (may be costly)
            File file = binary.getFile();
            length = file == null ? -1 : file.length();
        } else {
            length = blobInfo.length.longValue();
        }
        return new BinaryBlob(binary, blobKey, blobInfo.filename, blobInfo.mimeType, blobInfo.encoding,
                blobInfo.digest, length);
    }