Dereference of a possibly null reference.

In member Task UpdateHandler.HandleErrorAsync(ITelegramBotClient bot, Exception exception, HandleErrorSource source, CancellationToken cancellationToken), change parameter name bot to botClient in order to match the identifier as it has been declared in Task IUpdateHandler.HandleErrorAsync(ITelegramBotClient botClient, Exception exception, HandleErrorSource source, CancellationToken cancellationToken) (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1725)

Forward the 'cancellationToken' parameter to the 'Delay' method or pass in 'CancellationToken.None' explicitly to indicate intentionally not propagating the token (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2016)

In externally visible method 'void Startup.Configure(IFunctionsHostBuilder builder)', validate parameter 'builder' is non-null before using it. If appropriate, throw an 'ArgumentNullException' when the argument is 'null'. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1062)

For improved performance, use the LoggerMessage delegates instead of calling 'LoggerExtensions.LogInformation(ILogger, string?, params object?[])' (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1848)

Use PascalCase for named placeholders in the logging message template (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1727)

For improved performance, use the LoggerMessage delegates instead of calling 'LoggerExtensions.LogInformation(ILogger, string?, params object?[])' (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1848)

For improved performance, use the LoggerMessage delegates instead of calling 'LoggerExtensions.LogInformation(ILogger, string?, params object?[])' (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1848)

For improved performance, use the LoggerMessage delegates instead of calling 'LoggerExtensions.LogInformation(ILogger, string?, params object?[])' (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1848)