Last big release before going all-in on ASP.NET Core

Upgrade guide: http://fubardevelopment.github.io/FtpServer/articles/upgrade-3.0.html

What's new?

• In-memory file system
• Passive data connection port range (contribution from 40three GmbH)
• New IFtpServerHost interface
• New IFtpService interface which allows easy integration into ASP.NET Core
• New IAccountInformation interface
• New IAnonymousFtpUser interface

What's changed?

• Google drive upload without background uploader
• BREAKING: The FTP commands are now registered as singletons to improve performance
• BREAKING: Usage of ReadOnlySpan in the FTP command collector
• BREAKING: IFileSystemClassFactory.Create takes an IAccountInformation
• BREAKING: The IMembershipProvider is now asynchronous
• BREAKING: FtpConnectionData.IsAnonymous is obsolete, the anonymous user is now of type IAnonymousFtpUser
• The IFtpCommandHandler.GetExtensions() is now deprecated as all extensions that were previously returned here have their own implementation now

What's fixed?

• AUTH TLS fails gracefully when no SSL certificate is configured
• SITE BLST works again

A look into the future

The 4.x version will drop support for .NET Standard 1.3 and - eventually - .NET 4.6.1 as
the FTP Server will be reimplemented as ConnectionHandler which will result into the following
improvements:

• Easy hosting in an ASP.NET Core application
• Usage of pipelines when possible (AUTH TLS might cause problems)
• Using the ASP.NET Core connection state management