Add specific traffic metric entry for event streaming (#501)

Add traffic metric for event streaming

session/resthandler.go

@@ -634,6 +634,7 @@ func (handler *RestHandler) QueueRequestWithCallback(actionState *action.State,
 			failRequest(errors.WithStack(err))
 			return
 		}
+		doTs := time.Now()
 		request.response, errRequest = handler.Client.Do(req)
 		if errRequest != nil {
 			WarnOrError(actionState, logEntry, failOnError, errors.Wrap(errRequest, "HTTP request fail"))
@@ -648,6 +649,10 @@ func (handler *RestHandler) QueueRequestWithCallback(actionState *action.State,
 			request.ResponseStatusCode = request.response.StatusCode
 			request.ResponseHeaders = request.response.Header
 			request.ResponseBody, errRequest = io.ReadAll(request.response.Body)
+			// When content type is a stream normal metric log will be time to response without starting to stream the body. Thus this will log response time to stream end
+			if logEntry.ShouldLogTrafficMetrics() && strings.HasPrefix(request.response.Header.Get("Content-Type"), "text/event-stream") {
+				logEntry.LogTrafficMetric(time.Since(doTs).Nanoseconds(), 0, uint64(len(request.ResponseBody)), -1, req.URL.Path, "", "STREAM", "")
+			}
 		}
 	}()
 }