Keep local echo delegates at the bottom

TODO.md

@@ -5,6 +5,7 @@
 ideas
 (^/v) messages unread + messages still sending
 sticky avatar at top
+ability to cancel message being sent
 
 nio
 fix `RoomForgetResponse.create_error`

src/qml/EventHandlers/rooms.js

@@ -75,7 +75,12 @@ function onTimelineEventReceived(
         "targetUserId": target_user_id,
     }
 
-    // Replace any matching local echo
+    if (is_local_echo) {
+        timelines.append(item)
+        return
+    }
+
+    // Replace first matching local echo
     var found = timelines.getIndices({
         "roomId":       room_id,
         "senderId":     sender_id,

src/qml/Models/Timelines.qml

@@ -12,8 +12,11 @@ HListModel {
         }
     }
 
-    sorters: RoleSorter {
+    sorters: ExpressionSorter {
-        roleName: "date"
+        expression: modelLeft.isLocalEcho && ! modelRight.isLocalEcho ?
-        sortOrder: Qt.DescendingOrder
+                    true :
+                    ! modelLeft.isLocalEcho && modelRight.isLocalEcho ?
+                    false :
+                    modelLeft.date > modelRight.date // descending order
     }
 }