The log message to be formatted/computed.
The message format to use
The formatted log message.
%b: short UTC month name (Jan–Dec)%c: UTC timestamp shortcut (Mon dd hh:mm:ss)%d: 2-digit UTC day of month (01–31)%e: 2-digit UTC month with leading whitespace for single-digit months ( 1–12)%H: 2-digit UTC hour (00–23)%l: log level%M: 2-digit UTC minute (00–59)%m: 2-digit UTC month (01–12)%p: prefix (with trailing delimiter if present)%S: 2-digit UTC second (00–59)%s: message contents%Y: 4-digit UTC year
Formats the log message