docs: public static final void validateToken(AuthToken token) throws IllegalArgumentException {
          if (token.getExpiresOn().before(new Date())) {
              throw new IllegalArgumentException("Authentication token expired: " + token.getExpiresOn()); //$NON-NLS-1$
          }
          String validSig = generateSignature(token);
          if (token.getSignature() == null || !token.getSignature().equals(validSig)) {
              throw new IllegalArgumentException("Missing or invalid signature on the auth token."); //$NON-NLS-1$
          }
      }