do_helo

# File lib/net/smtp.rb, line 603
    def do_helo(helo_domain)
      res = @esmtp ? ehlo(helo_domain) : helo(helo_domain)
      @capabilities = res.capabilities
    rescue SMTPError
      if @esmtp
        @esmtp = false
        @error_occurred = false
        retry
      end
      raise
    end