Add a bunch of logging around sending messages

In an attempt to diagnose https://github.com/vector-im/riot-web/issues/4278,
add some debug to make the rageshakes more useful.

src/client.js

@@ -941,6 +941,8 @@ MatrixClient.prototype.sendEvent = function(roomId, eventType, content, txnId,
         txnId = this.makeTxnId();
     }
 
+    console.log(`sendEvent of type ${eventType} in ${roomId} with txnId ${txnId}`);
+
     // we always construct a MatrixEvent when sending because the store and
     // scheduler use them. We'll extract the params back out if it turns out
     // the client has no scheduler or store.
@@ -1065,7 +1067,12 @@ function _sendEventHttpRequest(client, event) {
 
     return client._http.authedRequest(
         undefined, "PUT", path, undefined, event.getWireContent(),
-    );
+    ).then((res) => {
+        console.log(
+            `Event sent to ${event.getRoomId()} with event id ${res.event_id}`,
+        );
+        return res;
+    });
 }
 
 /**

src/crypto/DeviceList.js

@@ -76,6 +76,10 @@ export default class DeviceList {
             if (this._keyDownloadsInProgressByUser[u]) {
                 // already a key download in progress/queued for this user; its results
                 // will be good enough for us.
+                console.log(
+                    `downloadKeys: already have a download in progress for ` +
+                    `${u}: awaiting its result`,
+                );
                 promises.push(this._keyDownloadsInProgressByUser[u]);
             } else if (forceDownload || trackingStatus != TRACKING_STATUS_UP_TO_DATE) {
                 usersToDownload.push(u);
@@ -88,6 +92,10 @@ export default class DeviceList {
             promises.push(downloadPromise);
         }
 
+        if (promises.length === 0) {
+            console.log("downloadKeys: already have all necessary keys");
+        }
+
         return q.all(promises).then(() => {
             return this._getDevicesFromStore(userIds);
         });

src/crypto/algorithms/megolm.js

@@ -183,6 +183,7 @@ MegolmEncryption.prototype._ensureOutboundSession = function(devicesInRoom) {
         }
 
         if (!session) {
+            console.log(`Starting new megolm session for room ${self._roomId}`);
             session = self._prepareNewSession();
         }
 
@@ -353,6 +354,8 @@ MegolmEncryption.prototype._shareKeyWithDevices = function(session, devicesByUse
         // TODO: retries
         return self._baseApis.sendToDevice("m.room.encrypted", contentMap);
     }).then(function() {
+        console.log(`Completed megolm keyshare in ${self._roomId}`);
+
         // Add the devices we have shared with to session.sharedWithDevices.
         //
         // we deliberately iterate over devicesByUser (ie, the devices we
@@ -387,6 +390,8 @@ MegolmEncryption.prototype._shareKeyWithDevices = function(session, devicesByUse
  */
 MegolmEncryption.prototype.encryptMessage = function(room, eventType, content) {
     const self = this;
+    console.log(`Starting to encrypt event for ${this._roomId}`);
+
     return this._getDevicesInRoom(room).then(function(devicesInRoom) {
         // check if any of these devices are not yet known to the user.
         // if so, warn the user so they can verify or ignore.

src/models/room.js

@@ -752,6 +752,8 @@ ALLOWED_TRANSITIONS[EventStatus.CANCELLED] =
  * @fires module:client~MatrixClient#event:"Room.localEchoUpdated"
  */
 Room.prototype.updatePendingEvent = function(event, newStatus, newEventId) {
+    console.log(`setting pendingEvent status to ${newStatus} in ${event.getRoomId()}`);
+
     // if the message was sent, we expect an event id
     if (newStatus == EventStatus.SENT && !newEventId) {
         throw new Error("updatePendingEvent called with status=SENT, " +