title: Firebase Analytics VIEW_ITEM_LIST ITEMS not showing
body: <p>I am trying to report a <a href="https://firebase.google.com/docs/reference/kotlin/com/google/firebase/analytics/FirebaseAnalytics.Event#view_item_list" rel="noreferrer">VIEW_ITEM_LIST</a> event with some <a href="https://firebase.google.com/docs/reference/kotlin/com/google/firebase/analytics/FirebaseAnalytics.Param#items" rel="noreferrer">ITEMS</a> inside. Everything is reported properly in the Debug View except for the items. I am not using any custom event. It seems to happen the same problem in both Android and iOS.</p>
  
  <p>Here is my code. </p>
  
  <pre><code> override fun trackListViewEvent() {
      val eventBundle = Bundle().apply {
          val itemBundle1 = Bundle().apply {
              putString(Param.ITEM_NAME, "name1")
              putString(Param.ITEM_CATEGORY, "Category")
              putString(Param.PRICE, "49.95")
              putString(Param.CURRENCY, "EUR")
          }
  
          val itemBundle2 = Bundle().apply {
              putString(Param.ITEM_NAME, "name2")
              putString(Param.ITEM_CATEGORY, "Category")
              putString(Param.PRICE, "89.95")
              putString(Param.CURRENCY, "EUR")
          }
              putString(Param.ITEM_LIST_ID, "1234567890")
              putString(Param.ITEM_LIST_NAME, "WhateverListName")
              putString(Param.PRICE, "125.60")
              putString(Param.CURRENCY, "EUR")
  
              putParcelableArray(Param.ITEMS, arrayOf(itemBundle1, itemBundle2))
          }
      tracking.logEvent(Event.VIEW_ITEM_LIST, eventBundle)
  }
  </code></pre>
  
  <p>In the Logcat I get: <code>W/FA-SVC: Param value can't be null: items
  </code></p>
  
  <p>Another problem is that it seems that ITEMS only accepts some parameters. When adding custom parameters I get <code>E/FA: Item cannot contain custom parameters</code>, but when adding NOT custom parameters like FLIGHT_NUMBER I get the same error. And I could not find any explanation on the documentation on which parameters are accepted.</p>