Nonzero offset implies a ranged request. Must also specify size.
size: number
A size > 0 implies a ranged request.
onload: (response:ArrayBuffer)=>void
Callback for successful fetch.
onerror: (msg?:string)=>void
Callback for fetch failure.
Returns void
See
IFetchHandler
Custom fetch handler
This provides a hook for the client application to
intercept requests for resources if they have to
be fetched in a way different than a simple HTTP get request.
Tutorial
If size = 0, a regular fetch of as much as possible is requested.
In this case, offset != 0 should not happen and is an error.
If size > 0, a fetch of a specific range is requested.
For Backwards compatibility only. Use new Interface for more flexibility