docs: public static int figureChunksNumber(final String fileName, final long fileLength, int chunkSize) {
        if (chunkSize < 0) {
           throw new IllegalStateException("Overflow in rescaling chunkSize. File way too large?");
        }
        final long numChunks = (fileLength % chunkSize == 0) ? (fileLength / chunkSize) : (fileLength / chunkSize) + 1;
        if (numChunks > Integer.MAX_VALUE) {
           log.rescalingChunksize(fileName, fileLength, chunkSize);
           chunkSize = 32 * chunkSize;
           return figureChunksNumber(fileName, fileLength, chunkSize);
        }
        else {
           return (int)numChunks;
        }
     }