I'm using version 2020.0.0-beta1.
Created the key pair with the command: ssh-keygen -t ecdsa -b 521
During the object creation
PrivateKeyFile keyFile = new PrivateKeyFile("c:..\id_ecdsa_private.key","passphrase")

I'm getting the error:
openssh key type: ecdsa-sha2-nistp521 is not supported
at Renci.SshNet.PrivateKeyFile.ParseOpenSshV1Key(Byte[] keyFileData, String passPhrase)
at Renci.SshNet.PrivateKeyFile.Open(Stream privateKey, String passPhrase)
at Renci.SshNet.PrivateKeyFile..ctor(String fileName, String passPhrase)
at Renci.SshNet.PrivateKeyFile..ctor(String fileName)
at Onboarding.Services.SFTPService.d__7.MoveNext() in C:\Projects...\SFTPService.cs:line 65

The documentation says SSH.NET supports the following host key algorithms:
...
ecdsa-sha2-nistp521
...
Can anyone tell me please what is wrong?
Thanks!