SFTP Download Files From Directory

Question

Can someone show an example in .NET (C#) on how to to connect to an SFTP server with an SFTP client and download all files in a folder, WITHOUT listing the files in that folder first? I am thinking with the help of PowerShell code in .NET or with a free nuget package.

I am connecting to the SFTP server with: IP, Port, username and ssh (private) key (in effect an array with one private key).

Thanks