website/build/ja/docs/api/classes/mediastreamtrack">MediaStreamTrack</a></p><h4><a aria-hidden="true" tabindex="-1" class="anchor enhancedAnchor_2LWZ" id="parameters-12"></a>Parameters<a class="hash-link" href="#parameters-12" title="Ë¶ãÂá∫„Åó„Å∏„ÅÆÁõ¥Êé•„É™„É≥„ÇØ">#</a></h4><table><thead><tr><th align="left">Name</th><th align="left">Type</th></tr></thead><tbody><tr><td align="left"><code>event?</code></td><td align="left"><code>string</code> | <code>symbol</code></