src/Pure/General/time.scala

--- a/src/Pure/General/time.scala	Sat Apr 04 18:05:37 2020 +0200
+++ b/src/Pure/General/time.scala	Sat Apr 04 18:13:05 2020 +0200
@@ -65,4 +65,6 @@
   }
 
   def instant: Instant = Instant.ofEpochMilli(ms)
+
+  def sleep { Thread.sleep(ms) }
 }