even.js

// all values optional,
// counters and timers are cumulative, 
// gauges are discrete, 
{
    "ts": <bson timesampt>,
    "id": <long, thread id, optional>, 
    "counters": {
	"n": <inc long>,
	"ops": <operations long>,
	"size": <bytes>,
	"errors": <long>,
    },
    "timers": {
	"duration": <operation duration ns>,
	"total": <total time duration ns>,
    },
    "gauges": {
	"state": <long, optional>, 
	"workers": <long>, 
	"failed": <bool>,
    }, 
}