BlobContainer container = new BlobContainer(tmpDir.toFile());
DigestBlob digestBlob = DigestBlob.resumeTransfer(
container, "417de3231e23dcd6d224ff60918024bc6c59aa58", transferId, 2);
BytesArray contentTail = new BytesArray("CDEFGHIJKLMN".getBytes());
digestBlob.addContent(contentTail, false);
BytesArray contentHead = new BytesArray("AB".getBytes());
digestBlob.addToHead(contentHead);
contentTail = new BytesArray("O".getBytes());