public class RetrieveMiningPoolByAddressQueryHandler : IRequestHandler<RetrieveMiningPoolByAddressQuery, MiningPool>
{
    private readonly IMediator _mediator;

    public RetrieveMiningPoolByAddressQueryHandler(IMediator mediator)
    {
        _mediator = mediator ?? throw new ArgumentNullException(nameof(mediator));
    }

    public Task<MiningPool> Handle(RetrieveMiningPoolByAddressQuery request, CancellationToken cancellationToken)
    {