mic.html worker example cuts the audio stream off early

[varenc]

The mic.html example (that uses mic.js) seems to cut the audio off about half a second too early. The amount it cuts off varies so I assume this related to the audio buffer boundary and the part of the audio stream isn't being passed to the lame encoder.

Any advice on what's wrong with mic.js that'll fix this? If I can fix this problem for myself I can contribute a pull request fixing it in the example as well.