Live Event Stream

A live event stream is a continuous feed that pushes each incoming event to the screen as it arrives, instead of returning the result of a query.

The browser holds an open connection, usually server-sent events or a WebSocket, and the server pushes records onto it; the screen keeps only a rolling buffer of the most recent items, so nothing from before the stream was opened is visible. Ordering follows arrival time rather than the time the action happened, which is why an event queued on an offline device lands out of place. The stream is a verification tool rather than a measurement tool: it shows that a newly instrumented event fires with the right properties, but it cannot say how many times it fired yesterday. Reading volume off a live stream is the standard misuse, because it only covers the window in which someone happened to be watching.