[question/proposal] Monitoring

[yklyahin]

What is the way to collect metrics for monitoring?
It would be good to get more information about the statistic of circuit breaker than just status: open, half-open and closed.

Count contains enough information about CB condition.

type Counts struct {
	Requests             uint32
	TotalSuccesses       uint32
	TotalFailures        uint32
	ConsecutiveSuccesses uint32
	ConsecutiveFailures  uint32
}