How to add custom property in meta property in api platform paginator

Question

I am using a state provider of API-Platfrom in symfony project to represent my data and using built-in API platform filters I need to add totalCost, the total number in the meta property in the paginated result.

I could not find any clear solution for that:

{
    "links": {
        "self": "/bmp-api/campaign-management/campaign-overview?page=1",
        "first": "/bmp-api/campaign-management/campaign-overview?page=1",
        "last": "/bmp-api/campaign-management/campaign-overview?page=821",
        "next": "/bmp-api/campaign-management/campaign-overview?page=2"
    },
    "meta": {
        "totalItems": 8210,
        "itemsPerPage": 10,
        "currentPage": 1
    },
    "data": [

this is my state provider:

class CampaignOverviewCollectionProvider implements ProviderInterface
{
    public function __construct(
        private readonly ProviderInterface $provider,
    ) {
    }

    public function provide(Operation $operation, array $uriVariables = [], array $context = [])
    {

        /** @var Paginator $campaignCollection */
        $campaignCollection = $this->provider->provide($operation, $uriVariables, $context);
        return $campaignCollection;
        }