[FEATURE-REQ] Ability to show loading spinner/text until the actual table row data is rendered

[happyvig]

First of all, great work on the add-on. Keep doing the great job.

It is a very common case where in, a particular component that is using the ember-table, has to fetch row data from remote via ember-concurrency task (instead of resolving in route's model hook) and there is a delay in actual data being bound and sent down to the ember-table.

In this scenario, it becomes a necessity to show a loader text or a spinner in the table body, until the actual data is received and rendered, for an acceptable/better user experience.

<EmberTable as |table|>
  <table.body
    ...
    @isLoading = {{this.fetchDataTask.isRunning}}
    @tableLoader = "Please wait ..."
    ...>
  </table.body>
<EmberTable>

(This also matches parity with ember-light-table in this particular aspect.) Thanks in advance.

Thoughts on this, guys ?

[pernambucano]

One idea would be to use the https://opensource.addepar.com/ember-table/docs/api/components/ember-tbody#lastReached method to see if we got to the last known item and then call a fetch function to add new items.