Store::incr('table', 'row', 'column', $by) increments an integer column atomically across all workers. No locks, no read-modify-write race — one syscall. Click +1. Open this URL in another window: every tab tracks the same value.
stored as ws_store_demo_data.shared_row.n · bumped via Store::incr()
Multiple tabs all subscribe to /ws/store-demo. Each bump POSTs to /api/learn/demo/store-bump, which calls Store::incr() and broadcasts the new value over the WebSocket to every connected client. This is what /learn/websocket uses for its real-time-sync section.