How do I output HTML from a text_long field in Twig? What is the alternative to the |raw filter if I want to output html from a entity field in twig in Drupal 8?

According to this ticket, |raw should be avoided, but I can't figure out how to use what they recommend in that ticket (Safestring/SafeMarkup) in twig.

I have a custom content entity that has a field definition as follows:

$fields['internal_description'] = BaseFieldDefinition::create('text_long')
  -&gt;setLabel(t('Internal description'))
  -&gt;setSettings(array(
    'max_length' =&gt; 1500,
  ))


The field stores HTML from a CKEditor instance. Now I would like to output this as HTML in a twig template. Currently if I just call 

{{  event.getExternalDescription }}


I get the escaped HTML as expected, however that is not what I want. If I do

{{  event.getExternalDescription | raw }}


I get what I want, which is unescaped, rendered HTML. However since it's not checked in any way in this case, I would like to know how to make this output safe and still allow my users to use CKEditor for entering content?
Normally you would configure the display of the field in UI.
You can do this in code by using the render element processed_text.
PHP
  $build = [
    '#type' =&gt; 'processed_text',
    '#text' =&gt; '&lt;p&gt;Hello world&lt;/p&gt;',
    '#format' =&gt; 'full_html',
  ];

TWIG
In twig you would use instead of the extremely unsafe {{ event.getExternalDescription | raw }} this code:
  {% set build = {
    '#type':   'processed_text',
    '#text':    event.getExternalDescription,
    '#format': 'full_html',
  } %}

  {{ build }}

The safety of the text format depends on the configuration of the text filters and the content of the field. Apply the same security considerations as you would for text formats in ckeditor.