Function flexi_logger::detailed_format

pub fn detailed_format(w: &mut Write, record: &Record) -> Result<(), Error>

A logline-formatter that produces log lines like
[2016-01-13 15:25:01.640870 +01:00] INFO [foo::bar] src/foo/bar.rs:26: Task successfully read from conf.json
i.e. with timestamp, module path and file location.