Cómo mostrar elementos de carga mientras se obtienen los datos de Firebase en android kotlin

Tengo un RecyclerView y mi Fragment. Estoy obteniendo datos de Firebase Realtime Database en un RecyclerView.

Necesito agregar un efecto de carga mientras se cargan los datos. ¿Cómo puedo hacer esto?

Código de mi Fragmento:

private var _binding: FragmentDayDetailBinding? = null
private val binding get() = _binding!!

private var ref: DatabaseReference? = null
private lateinit var adapter: DayDetailAdapter

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View {
    _binding = FragmentDayDetailBinding.inflate(inflater, container, false)

    setupRecyclerView()
    initDatabase()

    return binding.root
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)

    readFromDatabase()
}

private fun setupRecyclerView() {
    adapter = DayDetailAdapter()
    binding.recyclerView.layoutManager = LinearLayoutManager(requireContext())
    binding.recyclerView.adapter = adapter
}

private fun initDatabase() {
    FirebaseApp.initializeApp(requireContext())

    ref = FirebaseDatabase.getInstance()
        .getReference("IMIT")
        .child("groups")
}

private fun readFromDatabase() {
    ref?.addValueEventListener(object: ValueEventListener {
        override fun onDataChange(snapshot: DataSnapshot) {
            if (snapshot.exists()) {

                val list = ArrayList<day>()

                for (daySnapshot in snapshot.children) {
                    val day = daySnapshot.getValue(Day::class.java)

                    list.add(day!!)
                }

                adapter.submitList(list)

            } else {
                binding.apply {
                    lrDbEmpty.visibility = View.VISIBLE
                    recyclerView.visibility = View.INVISIBLE
                }
            }
        }

        override fun onCancelled(error: DatabaseError) {

        }
    })
}

override fun onDestroyView() {
    super.onDestroyView()
    _binding = null
}

Código del adaptador de RecyclerView:

“`
class ViewHolder(private val binding: ItemSubjectDetailBinding): RecyclerView.ViewHolder(binding.root) {

<pre><code>fun bind(day: Day) = with(binding) {
tvSubject.text = day.subject
tvInfo.text = "${day.teacher}, ${day.type}"
tvTime.text = day.time
tvAud.text = day.classroom
}

companion object {
fun from(parent: ViewGroup): ViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val binding = ItemSubjectDetailBinding.inflate(layoutInflater, parent, false)
return ViewHolder(binding)
}
}
</code></pre>

}

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder.from(parent)
}

override fun onBindViewHolder(holder: ViewHolder, position: Int) {
with(holder) {
bind(getItem(position))
}
}

class ItemComparator: DiffUtil.ItemCallback<day>() {
override fun areItemsTheSame(oldItem: Day, newItem: Day): Boolean {
return oldItem == newItem
}

<pre><code>override fun areContentsTheSame(oldItem: Day, newItem: Day): Boolean {
return oldItem == newItem
}
</code></pre>

}
“`