An RSET call implies that something bad has happened to the connection or the mailbox contents and automatically closes the connection to the server when called. This is an internal method, but can be called from your programs. Sends a user specified command to the POP3 server and returns a one line response . This method is useless if you need to read a multi-line response from the server. The corresponding carriage return line-feed pair will be stripped from the returned reply automatically.
Returns undef on failure.
If given a message number, returns the UIDL for that message. If called with no arguments, returns an associative array containing undeleted message number keys and their associated UIDL elements. Returns undef on failure. This deletes a specified message number. If no message number is specified, returns false.