message: pass room to _loadMembersIfJoined, it's called when newState not applied
  _loadMembersIfJoined is called from
  _onRoomLoaded < _onRoomViewStoreUpdate, before incoming state
  from the store is applied to this.state, so looking up the room
  with this.state.roomId doesn't always work, which would cause
  the members not to be loaded. Pass in the room instead.
diff: @@ -582,14 +582,13 @@ module.exports = React.createClass({
  this._warnAboutEncryption(room);
  this._calculatePeekRules(room);
  this._updatePreviewUrlVisibility(room);
  - this._loadMembersIfJoined();
  + this._loadMembersIfJoined(room);
  },
  - _loadMembersIfJoined: async function() {
  + _loadMembersIfJoined: async function(room) {
  // lazy load members if enabled
  if (SettingsStore.isFeatureEnabled('feature_lazyloading')) {
  const cli = MatrixClientPeg.get();
  - const room = cli.getRoom(this.state.roomId);
  if (room && room.getMyMembership() === 'join') {
  try {
  await room.loadMembersIfNeeded();
  