Document Supply.batch(:emit-timed)

lizmat++

Closes #4618

Author: coke

doc/Type/Supply.rakudoc

@@ -372,13 +372,17 @@ C<&mapper> and emits it to the new supply.
 
 =head2 method batch
 
-    method batch(Supply:D: :$elems, :$seconds --> Supply:D)
+    method batch(Supply:D: :$elems, :$seconds, :$emit-timed --> Supply:D)
 
 Creates a new supply that batches the values of the given supply by either
 the number of elements in the batch (using C<:elems>) or a duration
 (using C<:seconds>) or both.  Any remaining values are emitted in
 a final batch when the supply is done.
 
+When C<:emit-timed> is specified, a timer will run, emitting
+whatever is in the batch every given number of C<:seconds>, if the
+batch contains any values.
+
 B<Note>: Since Rakudo release 2020.12, the C<:seconds> parameter has
 a millisecond granularity: for example a 1 millisecond duration could
 be specified as C<:seconds(0.001)>. Before Rakudo release 2020.12,