New example: demonstrate using AudioBufferSourceNode + AudioBufferSource

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1. Load a sample using XMLHttpRequest
2. Decode using AudioContexts decodeAudioData
3. Create buffer source
4. Provide some controls to play/stop the buffer and also alter its attributes

Alternative more musical idea instead of controls for a single shot sample: use a piano keyboard or similar and make the sample play at different playbackRates
Here's a piano component - it might be relatively feasible to use or transform to use without Web Components https://github.com/openmusic/piano-keyboard

[sole]

An example is in mdn's repo https://github.com/mdn/fetch-examples/blob/gh-pages/fetch-array-buffer/index.html using Fetch