@Override
	protected boolean join(SubMemoryBlock block) throws IOException {
		if (!(block instanceof UninitializedSubMemoryBlock)) {
			return false;
		}
		setLength(subBlockLength + block.subBlockLength);
		adapter.deleteSubBlock(block.record.getKey());
		return true;
	}
Implementation of SubMemoryBlock for uninitialized blocks.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/mem/UninitializedSubMemoryBlock.java