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; };