message: Only emit in RoomViewStore when state actually changes
  This adds a shallow state check to attempt to only emit a store update when
  something actually changes.
  Fixes
diff: @@ -66,6 +66,20 @@ class RoomViewStore extends Store {
  }
  _setState(newState) {
  + // If values haven't changed, there's nothing to do.
  + // This only tries a shallow comparison, so unchanged objects will slip
  + // through, but that's probably okay for now.
  + let stateChanged = false;
  + for (const key of Object.keys(newState)) {
  + if (this._state[key] !== newState[key]) {
  + stateChanged = true;
  + break;
  + }
  + }
  + if (!stateChanged) {
  + return;
  + }
  +
  this._state = Object.assign(this._state, newState);
  this.__emitChange();
  }
  