add

# File activesupport/lib/active_support/logger_thread_safe_level.rb, line 59
    def add(severity, message = nil, progname = nil, &block) #:nodoc:
      severity ||= UNKNOWN
      progname ||= @progname

      return true if @logdev.nil? || severity < level

      if message.nil?
        if block_given?
          message  = yield
        else
          message  = progname
          progname = @progname
        end
      end

      @logdev.write          format_message(format_severity(severity), Time.now, progname, message)
    end