# File lib/net/smtp.rb, line 436
    def start(helo = 'localhost.localdomain',
              user = nil, secret = nil, authtype = nil)   # :yield: smtp

      if block_given?
        begin
          do_start(helo, user, secret, authtype)
          return yield(self)
        ensure
          do_finish
        end
      else
        do_start(helo, user, secret, authtype)
        return self
      end
    end