There must always be a stopsign visible to any concurrent reader no matter where it is. So before removing the old stopsign, the new one must be placed. You can only remove the old one if it was ahead of new one. If not, any readers scanning might have passed the location of the new one, and the old one might be gone before it gets there. And hence it will continue into space or a concrete wall.
There must always be a stopsign visible to any concurrent reader no matter where it is.
So before removing the old stopsign, the new one must be placed.
You can only remove the old one if it was ahead of new one.
If not, any readers scanning might have passed the location of the new one, and the old one might be gone
before it gets there. And hence it will continue into space or a concrete wall.

vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa