Annotation Interface Conditional
applicable to non native fields. if a conditional callback is set on the FSTObjectInput, the callback
will be called before the object referenced by the annotated field is decoded. Allows to skip decoding of
objects partially to save CPU.
WARNING: can be used for unshared (cycle free) Objects only. In addition all classes contained in the
skipped subgraph need to be preregistered. So applicable rarely. See git issue #75