Add config option to turn on in-room event sending timing metrics

This is intended to be hooked up to an external system. 

Due to the extra events and metadata concerns, this is only available if turned on from the config.

See `sendTimePerformanceMetrics.ts` for event schemas.

src/ContentMessages.tsx

@@ -39,6 +39,8 @@ import {
 import { IUpload } from "./models/IUpload";
 import { IAbortablePromise, IImageInfo } from "matrix-js-sdk/src/@types/partials";
 import { BlurhashEncoder } from "./BlurhashEncoder";
+import SettingsStore from "./settings/SettingsStore";
+import { decorateStartSendingTime, sendRoundTripMetric } from "./sendTimePerformanceMetrics";
 
 const MAX_WIDTH = 800;
 const MAX_HEIGHT = 600;
@@ -539,6 +541,10 @@ export default class ContentMessages {
             msgtype: "", // set later
         };
 
+        if (SettingsStore.getValue("Performance.addSendMessageTimingMetadata")) {
+            decorateStartSendingTime(content);
+        }
+
         // if we have a mime type for the file, add it to the message metadata
         if (file.type) {
             content.info.mimetype = file.type;
@@ -614,6 +620,11 @@ export default class ContentMessages {
         }).then(function() {
             if (upload.canceled) throw new UploadCanceledError();
             const prom = matrixClient.sendMessage(roomId, content);
+            if (SettingsStore.getValue("Performance.addSendMessageTimingMetadata")) {
+                prom.then(resp => {
+                    sendRoundTripMetric(matrixClient, roomId, resp.event_id);
+                });
+            }
             CountlyAnalytics.instance.trackSendMessage(startTime, prom, roomId, false, false, content);
             return prom;
         }, function(err) {

src/components/views/rooms/SendMessageComposer.tsx

@@ -54,6 +54,7 @@ import { Room } from 'matrix-js-sdk/src/models/room';
 import ErrorDialog from "../dialogs/ErrorDialog";
 import QuestionDialog from "../dialogs/QuestionDialog";
 import { ActionPayload } from "../../../dispatcher/payloads";
+import { decorateStartSendingTime, sendRoundTripMetric } from "../../../sendTimePerformanceMetrics";
 
 function addReplyToMessageContent(
     content: IContent,
@@ -418,6 +419,10 @@ export default class SendMessageComposer extends React.Component<IProps> {
             // don't bother sending an empty message
             if (!content.body.trim()) return;
 
+            if (SettingsStore.getValue("Performance.addSendMessageTimingMetadata")) {
+                decorateStartSendingTime(content);
+            }
+
             const prom = this.context.sendMessage(roomId, content);
             if (replyToEvent) {
                 // Clear reply_to_event as we put the message into the queue
@@ -433,6 +438,11 @@ export default class SendMessageComposer extends React.Component<IProps> {
                     dis.dispatch({ action: `effects.${effect.command}` });
                 }
             });
+            if (SettingsStore.getValue("Performance.addSendMessageTimingMetadata")) {
+                prom.then(resp => {
+                    sendRoundTripMetric(this.context, roomId, resp.event_id);
+                });
+            }
             CountlyAnalytics.instance.trackSendMessage(startTime, prom, roomId, false, !!replyToEvent, content);
         }
 

src/sendTimePerformanceMetrics.ts

@@ -0,0 +1,48 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { MatrixClient } from "matrix-js-sdk";
+
+/**
+ * Decorates the given event content object with the "send start time". The
+ * object will be modified in-place.
+ * @param {object} content The event content.
+ */
+export function decorateStartSendingTime(content: object) {
+    content['io.element.performance_metrics'] = {
+        sendStartTs: Date.now(),
+    };
+}
+
+/**
+ * Called when an event decorated with `decorateStartSendingTime()` has been sent
+ * by the server (the client now knows the event ID).
+ * @param {MatrixClient} client The client to send as.
+ * @param {string} inRoomId The room ID where the original event was sent.
+ * @param {string} forEventId The event ID for the decorated event.
+ */
+export function sendRoundTripMetric(client: MatrixClient, inRoomId: string, forEventId: string) {
+    // noinspection JSIgnoredPromiseFromCall
+    client.sendEvent(inRoomId, 'io.element.performance_metric', {
+        // XXX: We stick all of this into `m.relates_to` so it doesn't end up encrypted.
+        "m.relates_to": {
+            rel_type: "io.element.metric",
+            event_id: forEventId,
+            responseTs: Date.now(),
+            kind: 'send_time',
+        } as any, // override types because we're actually allowed to add extra metadata to relates_to
+    });
+}

src/settings/Settings.tsx

@@ -759,6 +759,10 @@ export const SETTINGS: {[setting: string]: ISetting} = {
         default: true,
         controller: new ReducedMotionController(),
     },
+    "Performance.addSendMessageTimingMetadata": {
+        supportedLevels: [SettingLevel.CONFIG],
+        default: false,
+    },
     "Widgets.pinned": { // deprecated
         supportedLevels: LEVELS_ROOM_OR_ACCOUNT,
         default: {},