New implementation for SSH, SCP and SFTP

[Arlodotexe]

Originally posted by @itsWindows11 in #12 (comment)

FTP and SFTP should be completely different implementations, as SFTP isn't the same as FTPS.

SSH.NET is basically the only actively maintained free SFTP/SCP library that I could find. Problem is it has some methods that are sync only, and others that are async but use the old Begin/End pattern, or async with callbacks, and finally async using Task, and it doesn't support checking the creation date of a file.

Instead of potentially exhausting the threadpool for IO if one were to stress test the SFTP implementation using that library, we might need a fork that properly makes use of Task and async, and maybe contribute back to the original repo.

We might need to look into adding progress reporting too in the abstraction if it already isn't there, Files might need it.

[Arlodotexe]

Tracking progress reporting in #54

[Arlodotexe]

Linking sshnet/SSH.NET#1415

[snargledorf]

I've recently started adding async implementations for some of the SFTP functions in the SSH.NET library. Just wanted to mention since I didn't see anyone else working on this.

I'm using the issue @Arlodotexe linked for tracking my PR's.

[itsWindows11]

@Arlodotexe

• There's also Tmds.Ssh which we could use as a separate implementation.
• Sounds like most of the concerns around SSH.NET async support are resolved if I'm not wrong. @snargledorf Are all I/O related methods migrated to async?

[snargledorf]

So far added:

• ExistsAsync
• GetAsync
• DeleteDirectoryAsync
• ChangeDirectoryAsync
• CreateDirectoryAsync

There is also a PR being worked on to add official support for DownloadFileAsync, UploadFileAsync and SynchronizeDirectoriesAsync.

Not sure if anyone else is working on any other async support, but these cover most of the basics IMO.

Not sure when a build of the library will occur that will include these changes.