title: Kivy doesn't play sound file the first time play() is called
body: <p>I run a simple Kivy app on Windows. A button executes following method from the Kivy docs (<a href="https://kivy.org/docs/api-kivy.core.audio.html" rel="nofollow noreferrer">link</a>) when pressed:</p>
  
  <pre><code>def play_audio(self):
      sound = SoundLoader.load('output.wav')
      if sound:
          print("Sound found at %s" % sound.source)
          print("Sound is %.3f seconds" % sound.length)
          sound.play()
  </code></pre>
  
  <p>The first time the button is pressed, it either plays about half a second of sound and then immediately stops or it's not playing anything at all. When I press the button again it plays the entire file as expected.</p>
  
  <p>Why isn't it playing the file on the first button press and how do I get it to work properly?</p>
  
  <p>Any help is greatly appreciated.</p>