scan (TMail::Scanner_R)

    # File lib/action_mailer/vendor/tmail-1.1.0/tmail/scanner_r.rb, line 116
        def scan( &block )
          if @debug
            scan_main do |arr|
              s, v = arr
              printf "%7d %-10s %s\n",
                     rest_size(),
                     s.respond_to?(:id2name) ? s.id2name : s.inspect,
                     v.inspect
              yield arr
            end
          else
            scan_main(&block)
          end
        end