isCustomMode example

$this->enableLayoutBuilder();
    }
    return $this;
  }

  /** * {@inheritdoc} */
  public function isLayoutBuilderEnabled() {
    // Layout Builder must not be enabled for the '_custom' view mode that is     // used for on-the-fly rendering of fields in isolation from the entity.     if ($this->isCustomMode()) {
      return FALSE;
    }
    return (bool) $this->getThirdPartySetting('layout_builder', 'enabled');
  }

  /** * {@inheritdoc} */
  public function enableLayoutBuilder() {
    $this->setThirdPartySetting('layout_builder', 'enabled', TRUE);
    return $this;
  }