- "FTP with CONNECT and slow server"
I believe this is not a problem these days.
- "FTP with NULs in URL parts"
The FTP protocol does not support them properly anyway.
- remove "FTP and empty path parts in the URL"
I don't think this has ever been reported as a real problem but was only
a hypothetical one.
- "Premature transfer end but healthy control channel"
This is not a bug, this is an optimization that *could* be performed but is
not an actual problem.
- "FTP without or slow 220 response"
Instead add to the documentation of the connect timeout that the
connection is considered complete at TCP/TLS/QUIC layer.
Closes#9979
