message: Fix MaxListenersExceededWarning
diff: @@ -658,6 +658,7 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
  callState: callState,
  });
  + CallHandler.instance.on(CallHandlerEvent.CallState, this.onCallState);
  window.addEventListener('beforeunload', this.onPageUnload);
  }
  @@ -675,7 +676,6 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
  }
  componentDidUpdate() {
  - CallHandler.instance.addListener(CallHandlerEvent.CallState, this.onCallState);
  if (this.roomView.current) {
  const roomView = this.roomView.current;
  if (!roomView.ondrop) {
  @@ -769,6 +769,8 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
  );
  }
  + CallHandler.instance.off(CallHandlerEvent.CallState, this.onCallState);
  +
  // cancel any pending calls to the throttled updated
  this.updateRoomMembers.cancel();
  