public final long getStartingOffset() {
		return subBlockOffset;
	}
Returns the starting offset for this sub block.  In other words, the first byte in this sub 
block is at this starting offset relative to the containing {@link MemoryBlockDB}

@return the starting offset for this sub block.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/mem/SubMemoryBlock.java