Instead of modifying the condition for updating the RR, separate the RM and RR conditions and use an OR to decide when to set both.
Make some logs only log when DEBUG.
If the RR event has been unpaginated, the logic in `sendReadReceipt` will now fallback on the event ID of the RM which in theory is always =< RR event ID stream-wise.
We started with clientSyncState being null, which it remained
until the SYNCING event was emitted. We need to set
clientSyncState's initial value correctly.
constantTimeDispatcher lets you poke a specific react component to do something
without having to do any O(N) operations. This is useful if you have thousands
of RoomTiles in a RoomSubList and want to just tell one of them to update,
without either having to do a full comparison of this.props.list or have each
and every RoomTile subscribe to a generic event from flux or node's eventemitter
*UNTESTED*
As detailed here https://docs.google.com/document/d/1UWqdS-e1sdwkLDUY0wA4gZyIkRp-ekjsLZ8k6g_Zvso/edit, the RM state is no longer kept locally, but rather server-side. The client now uses it's locally-calculated RM to update the server and receives server updates via the per-room account data.
The sending of the RR has been bundled in to reduce traffic when sending both. In effect, whenever a RR is sent the RM is sent with it but using the new API.
This uses a js-sdk change which has set to be finalised and so might change.
The actual fix to https://github.com/vector-im/riot-web/issues/3175 is this change to `_saveScrollState`, which is to pick the trackedScrollToken based on which node is intersected by the bottom of the scroll panel. This is opposed to the previous logic that picked based on which node was the first from the bottom to be above the bottom of the viewport.
In the case where the viewport bottom does not intersect any events, the topmost event is used.
Only zero the local notification count when we actually send a
read receipt, otherwise we cause a re-render of the RoomList every
time the user moves the cursor in the window, basically.
