package js.html;
typedef UnderlyingByteSource = {
@:optional
var autoAllocateChunkSize : Float;
@:optional
dynamic function cancel(reason:Dynamic):ts.AnyOf2>;
@:optional
dynamic function pull(controller:ReadableByteStreamController):ts.AnyOf2>;
@:optional
dynamic function start(controller:ReadableByteStreamController):ts.AnyOf2>;
var type : String;
};