public long getOptionalOffset() {
		return optionalOffset;
	}
Returns the offset of the procedure in the VFTable if intro/virtual. Value of -1 means
 there was not a value
@return the offset
Ghidra/Features/PDB/src/main/java/ghidra/app/util/bin/format/pdb2/pdbreader/type/AbstractMethodRecordMs.java