LogWriterFunc
typealias LogWriterFunc = (logLevel: LogLevelFlags, <Error class: unknown class>) -> LogWriterOutput
Writer function for log entries. A log entry is a collection of one or more #GLogFields, using the standard [field names from journal
specification](https://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html). See g_log_structured() for more information.
Writer functions must ignore fields which they do not recognise, unless they can write arbitrary binary output, as field values may be arbitrary binary.