#### 7.2.131 sleep-until

`(sleep-until TIME)`
  Suspend reading commands from this stream until TIME (in seconds). Commands already read will still be executed; `sleep-until` inside `progn` won't delay execution do rest do progn's contents. Time is measured according to this stream's clock, as set by `set-clock`; if never set, the first sleep-until sets it to 0 (so initially (sleep-until TIME) is the same as (sleep-for TIME)). Returns the number of seconds until TIME.