[Full Changelog](https://github.com/matrix-org/matrix-js-sdk/compare/v0.10.9...v0.11.0-rc.1)
* Support for lazy loading members. This should improve performance for
users who joined big rooms a lot. Pass to `lazyLoadMembers = true` option when calling `startClient`.
BREAKING CHANGES
----------------
* `MatrixClient::startClient` now returns a Promise. No method should be called on the client before that promise resolves. Before this method didn't return anything.
* A new `CATCHUP` sync state, emitted by `MatrixClient#"sync"` and returned by `MatrixClient::getSyncState()`, when doing initial sync after the `ERROR` state. See `MatrixClient` documentation for details.
* `RoomState::maySendEvent('m.room.message', userId)` & `RoomState::maySendMessage(userId)` do not check the membership of the user anymore, only the power level. To check if the syncing user is allowed to write in a room, use `Room::maySendMessage()` as `RoomState` is not always aware of the syncing user's membership anymore, in case lazy loading of members is enabled.
All Changes
-----------
* Only emit CATCHUP if recovering from conn error
[\#727](https://github.com/matrix-org/matrix-js-sdk/pull/727)
* Fix docstring for sync data.error
[\#725](https://github.com/matrix-org/matrix-js-sdk/pull/725)
* Re-apply "Don't rely on members to query if syncing user can post to room"
[\#723](https://github.com/matrix-org/matrix-js-sdk/pull/723)
* Revert "Don't rely on members to query if syncing user can post to room"
[\#721](https://github.com/matrix-org/matrix-js-sdk/pull/721)
* Don't rely on members to query if syncing user can post to room
[\#717](https://github.com/matrix-org/matrix-js-sdk/pull/717)
* Fixes for room.guessDMUserId
[\#719](https://github.com/matrix-org/matrix-js-sdk/pull/719)
* Fix filepanel also filtering main timeline with LL turned on.
[\#716](https://github.com/matrix-org/matrix-js-sdk/pull/716)
* Remove lazy loaded members when leaving room
[\#711](https://github.com/matrix-org/matrix-js-sdk/pull/711)
* Fix: show spinner again while recovering from connection error
[\#702](https://github.com/matrix-org/matrix-js-sdk/pull/702)
* Add method to query LL state in client
[\#714](https://github.com/matrix-org/matrix-js-sdk/pull/714)
* Fix: also load invited members when lazy loading members
[\#707](https://github.com/matrix-org/matrix-js-sdk/pull/707)
* Pass through function to discard megolm session
[\#704](https://github.com/matrix-org/matrix-js-sdk/pull/704)