Optionalonloadcb: Functionfunction to be called when the resource is loaded
Optionalonerrorcb: Functionfunction to be called in case of error
Optionalsettings: Object = {}custom settings to apply to the request (@link https://developer.mozilla.org/en-US/docs/Web/API/fetch#options)
the amount of asset loaded (always 1 if successfull)
Load an audio file