setAppId example

$entity = new CustomEntityEntity();

        $entity->setId('123');
        static::assertEquals('123', $entity->getId());

        $entity->setName('Test Entity');
        static::assertEquals('Test Entity', $entity->getName());

        $entity->setStoreApiAware(true);
        static::assertTrue($entity->getStoreApiAware());

        $entity->setAppId('app-123');
        static::assertEquals('app-123', $entity->getAppId());

        $entity->setPluginId('plugin-123');
        static::assertEquals('plugin-123', $entity->getPluginId());

        $fields = [
            [
                'name' => 'field1',
            ],
            [
                'name' => 'field2',
            ],

$taxProvider->setIdentifier(
                \sprintf('app\\%s_%s', $appName ?? self::META_APP_NAME, $provider->getIdentifier()),
            );

            $result->add($taxProvider);

            if (!$appId || !$appName) {
                continue;
            }

            $taxProvider->setProcessUrl($provider->getProcessUrl());
            $taxProvider->setAppId($appId);
        }

        return new EntitySearchResult(
            TaxProviderDefinition::ENTITY_NAME,
            $result->count(),
            $result,
            null,
            new Criteria(),
            Context::createDefaultContext()
        );
    }
}