code: @Override
      protected String canonicalize(final HttpURLConnection conn, final String accountName, final Long contentLength)
              throws StorageException {
  
          if (contentLength < -1) {
              throw new InvalidParameterException(SR.INVALID_CONTENT_LENGTH);
          }
  
          return canonicalizeTableHttpRequest(conn.getURL(), accountName, conn.getRequestMethod(),
                  Utility.getStandardHeaderValue(conn, Constants.HeaderConstants.CONTENT_TYPE), contentLength, null,
                  conn);
      }
docs: Constructs a canonicalized string for signing a request.
  
  @param conn
  the HttpURLConnection to canonicalize
  @param accountName
  the account name associated with the request
  @param contentLength
  the length of the content written to the outputstream in bytes, -1 if unknown
  @return a canonicalized string.
  @throws StorageException