Cannot use 'audio/webm; codecs=opus' mimeType

[LiubaLozynska]

Hey there!

Tying to use this polyfill in order to record audio with mime type 'audio/webm; codecs=opus' on IOS. However, in fact mimeType that is used is audio/webm without codec, even in Chrome and Firefox. Here is an online example https://jsfiddle.net/jcwomb13/1/ I have changes mimeType to 'audio/webm; codecs=opus', but as you can see in console mimeType is audio/webm. How can I make it 'audio/webm; codecs=opus'?

Thanks in advance for your help!