f any media in previous periods still
     to be played.</dd>
<dd><code>bufferedDurationUs</code> - The duration of media currently buffered from the current playback
     position, in microseconds. Note that the next load position can be calculated as <code>
     (playbackPositionUs + bufferedDurationUs)</code>.</dd>
<dd><code>availableDurationUs</code> - The duration of media available for buffering from the current
     playback position, in microseconds, or <a href="../C.html#TIME_UNSET"><code>C.TIME_UN