Python LogRecord has the attribute relativeCreated

Time in milliseconds when the LogRecord was created, relative to the time the logging module was loaded.

It's currently possible to use FluentRecordFormatter to include that in the fluent events

version: 1
formatters:
 fluent_fmt:
 '()': fluent.handler.FluentRecordFormatter
 format:
 "host.hostname": '%(hostname)s'
 "host.id": '%(hostname)s'
 "host.uptime": '%(relativeCreated)d'
 "log.logger": '%(name)s'
 "log.level": '%(levelname)s'
 "log.origin.file.name": '%(pathname)s'
 "log.origin.file.line": '%(lineno)d'
 "log.origin.function": '%(funcName)s'

but relativeCreated is in milliseconds, it would be very convenient to be able to convert that to seconds right in FluentRecordFormatter hence this feature request, please considering allowing something like

 "host.uptime": '%(relativeCreatedInSeconds)d'

were the relativeCreatedInSeconds would be something added by FluentRecordFormatter.