The log content sent to Loki. The default is the body of the Loggie event
Loki's log data structure is roughly divided into label and main data. By default, Loggie will convert the meta-information field in the header into a label connected with _.
In addition, it should be noted that since loki's labels key does not support ., /, -, the keys containing these symbols in the header will be automatically converted into _ form.