A Transformer is a VRL script used to transform a log record into another.
They are used to parse, refine, and enrich log records within a pipeline.
A common use case is to parse log records comming from syslog:
. = parse_syslog!(.message)
.
The above script expects a record with a single field message, containing text
in the syslog format. After processing, the resulting record will have
fields such as program, timestamp, or hostname.