chore: log when we've got an event where time's gone wobbly (#137)

## Which problem is this PR solving?

- In service to debugging #114 

## Short description of the changes

- added log output to assist debugging what makes an HTTP event appear
to have been responded to before the request was sent 😁

assemblers/http_reader.go

@@ -91,12 +91,22 @@ func (h *httpReader) run(wg *sync.WaitGroup) {
 }
 
 func (h *httpReader) processEvent(ident string, entry *entry) {
+	eventDuration := entry.responseTimestamp.Sub(entry.requestTimestamp)
+	if eventDuration < 0 { // the response came in before the request? wat?
+		// logging the weirdness for now so we can debug in environments with production loads
+		log.Debug().
+			Str("ident", ident).
+			Int64("duration_ns", int64(eventDuration)).
+			Int64("duration_ms", eventDuration.Milliseconds()).
+			Msg("Time has gotten weird for this event.")
+	}
+
 	h.parent.events <- HttpEvent{
 		RequestId: ident,
 		Request:   entry.request,
 		Response:  entry.response,
 		Timestamp: entry.requestTimestamp,
-		Duration:  entry.responseTimestamp.Sub(entry.requestTimestamp),
+		Duration:  eventDuration,
 		SrcIp:     h.srcIp,
 		DstIp:     h.dstIp,
 	}