newFetcher
fun newFetcher(data: Any, options: Options, imageLoader: ImageLoader, startIndex: Int = 0): Pair<Fetcher, Int>?
Create a new Fetcher using the registered fetcherFactories.
Return
A Pair where the first element is the new Fetcher and the second element is the index of the factory in fetcherFactories that created it. Returns 'null' if a Fetcher cannot be created for data.