Fix timestamps for Send errors

Previously, failed requests lost their start timing data (which wasn't
preserved from partial results when errors were thrown) and ignored the
timestamp for the failure itself entirely. Additionally, start times
could be entirely unset in some plausible cases if an error were thrown
before request-start fired. This is now handled more carefully, to
ensure that error durations are tracked correctly.

src/model/send/send-store.ts

@@ -107,19 +107,21 @@ export class SendStore {
             headers: rawHeadersToHeaders(requestInput.headers),
             rawHeaders: requestInput.headers,
             body: { buffer: encodedBody },
-            timingEvents: {} as TimingEvents,
+            timingEvents: {
+                startTime: Date.now()
+            } as TimingEvents,
             tags: ['httptoolkit:manually-sent-request']
         });
 
         // Keep the exchange up to date as response data arrives:
         trackResponseEvents(responseStream, exchange)
-        .catch(action((error: ErrorLike) => {
+        .catch(action((error: ErrorLike & { timingEvents?: TimingEvents }) => {
             exchange.markAborted({
                 id: exchange.id,
                 error: error,
                 timingEvents: {
                     ...exchange.timingEvents as TimingEvents,
-                    abortedTimestamp: performance.now()
+                    ...error.timingEvents
                 },
                 tags: error.code ? [`passthrough-error:${error.code}`] : []
             });
@@ -152,7 +154,6 @@ const trackResponseEvents = flow(function * (
         const messageType = value.type;
         switch (messageType) {
             case 'request-start':
-                timingEvents.startTime = Date.now();
                 timingEvents.startTimestamp = value.timestamp;
                 timingEvents.bodyReceivedTimestamp = value.timestamp;
                 break;
@@ -182,11 +183,15 @@ const trackResponseEvents = flow(function * (
                 break;
             case 'error':
                 if (value.error.message) {
+                    timingEvents.startTimestamp ??= value.timestamp; // If request not yet started
+                    timingEvents.abortedTimestamp = value.timestamp;
+
                     throw Object.assign(
                         new Error(value.error.message + (
                             value.error.code ? ` (${value.error.code})` : ''
                         )), {
-                            code: value.error.code
+                            code: value.error.code,
+                            timingEvents
                         }
                     );
                 } else {