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.
591 -> FTP multi PORT and 425 on upload
592 -> FTP multi PORT and 421 on upload
593 -> FTP multi PORT upload, no data conn and no transient neg. reply
594 -> FTP multi PORT upload, no data conn and no positive prelim. reply
1206 -> FTP PORT and 425 on download
1207 -> FTP PORT and 421 on download
1208 -> FTP PORT download, no data conn and no transient negative reply
1209 -> FTP PORT download, no data conn and no positive preliminary reply
