FObjectRefrepresents a heavyweight reference that contains the specific pieces of information needed to reference an object (or null) that may or may not be loaded yet. The expectation is that given the imports of a package we have loaded, we should be able to create anFObjectRefto objects in a package we haven't yet loaded. For this reason,FObjectRefhas to be derivable from the serialized (not transient) contents of anFObjectImport.