Text is sent only after a numeric status response line has been sent
   that indicates that text will follow.  Text is sent as a series of
   successive lines of textual matter, each terminated with CR-LF pair.
   A single line containing only a period (.) is sent to indicate the
   end of the text (i.e., the server will send a CR-LF pair at the end
   of the last line of text, a period, and another CR-LF pair).

   If the text contained a period as the first character of the text
   line in the original, that first period is doubled.  Therefore, the
   client must examine the first character of each line received, and
   for those beginning with a period, determine either that this is the
   end of the text or whether to collapse the doubled period to a single
   one.

   The intention is that text messages will usually be displayed on the
   user's terminal whereas command/status responses will be interpreted
   by the client program before any possible display is done.