Support for RFC2389 in Net::FTP
This patch implements RFC 2389 in the stdlib implementation of Net::FTP.
RFC 2389 is used to make FTP extensions discoverable and provides a way to interact with them through the FEAT and OPTS commands. A very common use case for this is where an FTP server needs to have UTF8 filename support explicitly enabled.
Patch provides two new methods,
features for returning an array of supported extensions and
option for configuring them.