code: @Nonnull
    public final JettyStarter setStopKey (@Nonnull final String sStopKey)
    {
      ValueEnforcer.notNull (sStopKey, "StopKey");
      m_sStopKey = sStopKey;
      return this;
    }
docs: Set the hidden "stop key" that must be submitted to stop the server.
  Defaults to {@link #DEFAULT_STOP_KEY}. If set here, it must also be set in
  {@link JettyStopper}.
  
  @param sStopKey
  The stop key to be used. May not be <code>null</code>.
  @return this for chaining