ExampleServiceClassicDecorator.cs

internal sealed class ExampleServiceClassicDecorator : IExampleService
{
    private readonly IExampleService _decorated;

    private readonly ILogger<ExampleServiceClassicDecorator> _logger;

    public ExampleServiceClassicDecorator(IExampleService decorated, 
        ILogger<ExampleServiceClassicDecorator> logger)
    {
        _decorated = decorated;
        _logger = logger;
    }

    /// <inheritdoc />
    public async Task VeryImportantWorkAsync(int additionalSecondsToWait)
    {
        _logger.LogInformation("Log something before method call");
        await _decorated.VeryImportantWorkAsync(additionalSecondsToWait);
        _logger.LogInformation("Log something after method competition.");
    }
}