@:implnew (data:DataPointer, length:Int, memoryMode:Int)
@:implread onlydata:DataPointer
@:implread onlydataWritable:DataPointer
@:implread onlyimmutable:Bool
@:implread onlylength:Int
@:implcreateSubBlob (this:CFFIPointer, offset:Int):HBBlob
@:implmakeImmutable ():Void
staticread onlyempty:HBBlob