Send a NOOP command to the POP3 server. This is useful for keeping a connection alive since most POP3 servers will timeout after 10 minutes of inactivity. A noop attempt will only succeed if the client is in the {@link org.apache.commons.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE }.
@return True if the noop attempt was successful, false if not.
@exception IOException If a network I/O error occurs in the process ofsending the NOOP command.