Fix potential memory leak in video player sample.

samples/videoplayer/src/videoPlayerMain/kotlin/DecoderWorker.kt

@@ -316,7 +316,7 @@ private class Decoder(
     fun audioVideoSynced() = (audio?.isSynced() ?: true) || done()
 }
 
-class DecoderWorker(val worker: Worker) : Disposable {
+inline class DecoderWorker(val worker: Worker) : Disposable {
     // This class must have no other state, but this worker object.
     // All the real state must be stored on the worker's side.
     constructor() : this(Worker.start())

samples/videoplayer/src/videoPlayerMain/kotlin/SDLAudio.kt

@@ -65,15 +65,10 @@ class SDLAudio(val player: VideoPlayer) : DisposableContainer() {
     }
 }
 
-// Only set in the audio thread
-@ThreadLocal
-private var decoder: DecoderWorker? = null
-
 private fun audioCallback(userdata: COpaquePointer?, buffer: CPointer<Uint8Var>?, length: Int) {
     // This handler will be invoked in the audio thread, so reinit runtime.
     kotlin.native.initRuntimeIfNeeded()
-    val decoder = decoder ?:
-        DecoderWorker(Worker.fromCPointer(userdata)).also { decoder = it }
+    val decoder = DecoderWorker(Worker.fromCPointer(userdata))
     var outPosition = 0
     while (outPosition < length) {
         val frame = decoder.nextAudioFrame(length - outPosition)
@@ -88,4 +83,4 @@ private fun audioCallback(userdata: COpaquePointer?, buffer: CPointer<Uint8Var>?
             break
         }
     }
-}
+}