public class LoggingAuthorizationHandler : AuthorizationHandler<MyRequirement>
{
    ILogger _logger;

    public LoggingAuthorizationHandler(ILoggerFactory loggerFactory)
    {
        _logger = loggerFactory.CreateLogger(this.GetType().FullName);
    }

    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, MyRequirement requirement)
    {
        _logger.LogInformation("Inside my handler");
        // Check if the requirement is fulfilled.
        return Task.CompletedTask;
    }
}

services.AddSingleton<IAuthorizationHandler, LoggingAuthorizationHandler>();