Translate a node programmatically

Exemples:

$translation = $entity->getTranslation('de');

$translation = \Drupal::entityManager()->getTranslationFromContext($entity);

$node_es = $node->addTranslation('es');

$node_es->title = 'Mi prueba!';

$node_es->body->value = '<p>El cuerpo de mi nodo.</p>';

$node_es->body->format = 'full_html';

$node_es->save();