docs: public static String calculateTreeHash(File file)
              throws AmazonClientException {
          ResettableInputStream is = null;
          try {
              is = new ResettableInputStream(file);
              return calculateTreeHash(is);
          } catch (IOException e) {
              throw new AmazonClientException("Unable to compute hash for file: "
                      + file.getAbsolutePath(), e);
          } finally {
              if (is != null)
                  is.release();
          }
      }