code: @Nonnull
    public DigestAuthServerBuilder setStale (@Nonnull final ETriState eStale)
    {
      m_eStale = ValueEnforcer.notNull (eStale, "Stale");
      return this;
    }
docs: A flag, indicating that the previous request from the client was rejected
  because the nonce value was stale. If stale is TRUE (case-insensitive), the
  client may wish to simply retry the request with a new encrypted response,
  without reprompting the user for a new username and password. The server
  should only set stale to TRUE if it receives a request for which the nonce
  is invalid but with a valid digest for that nonce (indicating that the
  client knows the correct username/password). If stale is FALSE, or anything
  other than TRUE, or the stale directive is not present, the username and/or
  password are invalid, and new values must be obtained.
  
  @param eStale
  Stale value. May not be <code>null</code>.
  @return this