If a handler doesn't explicitly call `WriteHeader` before `Write` then the status code is set to `http.StatusOK` but `measured_http.MeasuredHandler` doesn't handle this which results in reporting `0` as the response code.
Uses a special mux for the OCSP Responder so that we stop collapsing double slashes in GET requests which cause a small number of requests to be considered malformed.
Rename HTTPMonitor to MeasuredHandler.
Remove inflight stat (we didn't use it).
Add timing stat by method, endpoint, and status code.
The timing stat subsumes the "rate" stat, so remove that.
WFE now wraps in MeasuredHandler, instead of relying on its cmd/main.go.
Remove FBAdapter stats.
MeasuredHandler tracks stats by method, status code, and endpoint.
In VA, add a Prometheus histogram for validation timing.
Samantha Frank
Roland Bracewell Shoemaker
Jacob Hoffman-Andrews