StateLiveData.kt

import androidx.lifecycle.LifecycleOwner
import androidx.lifecycle.LiveData

 interface StateLiveData<R, E> {
  fun observe(owner: LifecycleOwner, onSuccess: (R) -> Unit, onError: (E) -> Unit = {}, onLoading: (Boolean) -> Unit = {})
  val loadingLiveData: LiveData<Boolean>
  val successLiveData: LiveData<R>
  val errorLiveData: LiveData<E>
}

StateMutableLiveData.kt

import androidx.lifecycle.LifecycleOwner
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.Observer

 class StateMutableLiveData<R, E> : StateLiveData<R, E> {
  val success = MutableLiveData<R>()
  val loading = MutableLiveData<Boolean>()
  val error = MutableLiveData<E>()

  override val loadingLiveData: LiveData<Boolean> get() = loading
  override val successLiveData: LiveData<R> get() = success
  override val errorLiveData: LiveData<E> get() = error

  override fun observe(owner: LifecycleOwner, onSuccess: (R) -> Unit, onError: (E) -> Unit, onLoading: (Boolean) -> Unit) {
   successLiveData.observe(owner, Observer {
     onSuccess.invoke(it)
   })

     loadingLiveData.observe(owner, Observer {
      onLoading.invoke(it)
    })

     errorLiveData.observe(owner, Observer {
      onError.invoke(it)
    })
  }
}