docs: public void changeAvailabilityStatus(String status, Presence.Mode mode) throws NotConnectedException, InterruptedException, MucNotJoinedException {
          final EntityFullJid myRoomJid = this.myRoomJid;
          if (myRoomJid == null) {
              throw new MucNotJoinedException(this);
          }
  
          // Check that we already have joined the room before attempting to change the
          // availability status.
          if (!joined) {
              throw new MucNotJoinedException(this);
          }
          // We change the availability status by sending a presence packet to the room with the
          // new presence status and mode
          Presence joinPresence = new Presence(Presence.Type.available);
          joinPresence.setStatus(status);
          joinPresence.setMode(mode);
          joinPresence.setTo(myRoomJid);
  
          // Send join packet.
          connection.sendStanza(joinPresence);
      }