title: using ExoPlayer with kotlin
body: <p>I want to use ExoPlayer using kotlin, I saw code for that but my compiler can't recognize 'buildRenderersFactory' reference.
  Can someone help?
  I'm using android studio
  and implement:
  def exoPlayerVersion = &quot;2.9.0&quot;
  implementation &quot;com.google.android.exoplayer:exoplayer:$exoPlayerVersion&quot;</p>
  <pre><code>private val defaultBandwidthMeter = DefaultBandwidthMeter.Builder(context).build()
  
  private val dataSourceFactory: DefaultDataSourceFactory
  
  private val extractorsFactory = DefaultExtractorsFactory()   
  
  private val renderersFactory = buildRenderersFactory(useExtensionRenderers = true, preferExtensionRenderer = true)
  
  val exoPlayer :SimpleExoPlayer =  ExoPlayerFactory.newSimpleInstance(context, renderersFactory,  DefaultTrackSelector(), DefaultLoadControl())
  
  val dataSourceFactory = DefaultDataSourceFactory(context, defaultBandwidthMeter, DefaultHttpDataSourceFactory(Util.getUserAgent(context, &quot;MKDPlayer&quot;),  defaultBandwidthMeter))
  
  val mediaSource = ProgressiveMediaSource.Factory(dataSourceFactory,extractorsFactory)
      .setCustomCacheKey(&quot;ExoPlayerAdapter&quot;)
      .createMediaSource(uri)
      
  exoPlayer.prepare(mediaSource)
  </code></pre>