ObjFileSourcePrivate to ensure the phantom tag is injective
marshal_out_binary oh segment is a low level, stateful, API returning oc, stop. Once called no other API can be used on the same oh and only Stdlib.output_* APIs should be used on oc. stop () must be invoked in order to signal that all data was written to oc (which should not be used afterwards). Only after calling stop the other API can be used on oh.