code: private function unFreeze()
      {
          $this->isFrozen = false;
          $this->isReplay = null;
  
          foreach (static::schema()->getFields() as $field) {
              if ($field->getType()->isMessage()) {
                  /** @var self $value */
                  $value = $this->get($field->getName());
                  if (empty($value)) {
                      continue;
                  }
  
                  if ($value instanceof Message) {
                      $value->unFreeze();
                      continue;
                  }
  
                  /** @var self $v */
                  foreach ($value as $v) {
                      $v->unFreeze();
                  }
              }
          }
      }
docs: Recursively unfreezes this object and any of its children.
  Used internally during the clone process.