Async loading

[hrj]

(start decoding while the bytes are still being fetched from the network)

[hrj]

Good discussion / ideas about synchronisation in web-workers:
http://stackoverflow.com/questions/43038023/obtain-data-synchronously-from-webworker

To summarize:

• One could use a polling loop to read data from local-storage, but this will spin the CPU.
• In future, SharedArrayBuffer will help. It is supported in Firefox and Safari now, but not yet standardized, nor available in other browsers. Edit: Atomics.wait seems especially useful.

[hrj]

Update:

Atomics.wait was gaining support in major browsers. However, recently, the support has been disabled by most browsers to reduce the efficacy of side-channel attacks. So we are back to where we were, until the support is re-enabled.