Pauses the flow for a fixed number of milliseconds, then continues.Mostly a dev tool: insert it between steps to slow a run down so you can
watch the Runs pane fill in, or to reproduce timing-sensitive behaviour.
It has no effect on the data flowing through — it just waits.
The pause blocks the run for its whole duration; cancellation is only
checked between nodes, so a sleeping node finishes its wait before a
cancel is honoured. The 60 s ceiling keeps a stray node from wedging a
run.