private Address createOverlaySpace(String name, Address start, long dataLength)
			throws IllegalStateException, AddressOverflowException, LockException {

		start.addNoWrap(dataLength - 1);// just tests the AddressOverflow condition.

		ProgramOverlayAddressSpace ovSpace =
			createUniqueOverlaySpace(name, start.getAddressSpace());

		Address ovAddr = ovSpace.getAddressInThisSpaceOnly(start.getOffset());
		return ovAddr;
	}
Two blocks have been joined producing newBlock. The block which was eliminated can be
identified using the oldBlockStartAddr.

@param newBlock new joined memory block
@param oldBlockStartAddr original start address of affected block
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/mem/MemoryMapDB.java