Remove InlineWorker from closure in getAudioDecoder

[davidturissini]

getAudioDecoder creates an InlineWorker on every invocation. This is ok for processing a single waveform, but it quickly becomes a problem when multiple waveforms are processed. It would be better if the worker was created only once.

[chrisn]

Ah, good point. I'm happy to pick this up, unless you're already working on it?

[davidturissini]

@chrisn go for it. I have a couple ideas but haven’t started yet.