1- Two new error codes are introduced.
CURLE_FTP_ACCEPT_FAILED to be set whenever ACCEPTing fails because of
FTP server connected.
CURLE_FTP_ACCEPT_TIMEOUT to be set whenever ACCEPTing timeouts.
Neither of these errors are considered fatal and control connection
remains OK because it could just be a firewall blocking server to
connect to the client.
2- One new setopt option was introduced.
CURLOPT_ACCEPTTIMEOUT_MS
It sets the maximum amount of time FTP client is going to wait for a
server to connect. Internal default accept timeout is 60 seconds.
CURLINFO_APPCONNECT_TIME. This is set with the "application layer"
handshake/connection is completed (typically SSL, TLS or SSH). By using this
you can figure out the application layer's own connect time. You can extract
the time stamp using curl's -w option and the new variable named
'time_appconnect'. This feature was sponsored by Lenny Rachitsky at NeuStar.