code: public LogoutUrlBuilder logoutUrl(String returnToUrl, boolean setClientId) {
          Asserts.assertValidUrl(returnToUrl, "return to url");
  
          return LogoutUrlBuilder.newInstance(baseUrl, clientId, returnToUrl, setClientId);
      }
docs: Creates an instance of the {@link LogoutUrlBuilder} with the given return-to url.
  i.e.:
  <pre>
  {@code
  AuthAPI auth = new AuthAPI("me.auth0.com", "B3c6RYhk1v9SbIJcRIOwu62gIUGsnze", "2679NfkaBn62e6w5E8zNEzjr-yWfkaBne");
  String url = auth.logoutUrl("https://me.auth0.com/home", true)
  .useFederated(true)
  .withAccessToken("A9CvPwFojaBIA9CvI");
  }
  </pre>
  
  @param returnToUrl the redirect_uri value to set, white-listed in the Application settings. Must be already URL Encoded.
  @param setClientId whether the client_id value must be set or not. This affects the white-list that the Auth0's Dashboard uses to validate the returnTo url.
  @return a new instance of the {@link LogoutUrlBuilder} to configure.