public async Task <IActionResult> CancelarPostAsync(Guid id)
        {
            var reuniao = await ObterReuniaoAsync(id);

            var command = new CancelarReuniaoCommand()
            {
                Reuniao = reuniao
            };

            await mediator.Send(command);

            return(NoContent());
        }
        public async Task <Unit> Handle(CancelarReuniaoCommand request, CancellationToken cancellationToken)
        {
            request.Reuniao.Cancelar();

            return(await ProcederComAAtualizacaoDaReuniaoAsync(request.Reuniao));
        }