Make sure Supply.rotor handles different threads

src/core/SupplyOperations.pm

@@ -286,36 +286,26 @@ my class SupplyOperations is repr('Uninstantiable') {
         $overlap //= 1;
         return $s if $elems == 1 and $overlap == 0;  # nothing to do
 
-        my class RotorSupply does Supply does PrivatePublishing {
-            has $!source;
-            has $.elems;
-            has $.overlap;
-
-            submethod BUILD(:$!source, :$!elems, :$!overlap) { }
-
-            method tap(|c) {
-                my $source_tap;
-                my $tap = self.Supply::tap(|c, closing => { $source_tap.close() });
-
+        on -> $res {
+            $s => do {
                 my @batched;
                 sub flush {
-                    self!more([@batched]);
-                    @batched.splice( 0, +@batched - $!overlap );
+                    $res.more( [@batched] );
+                    @batched.splice( 0, +@batched - $overlap );
                 }
 
-                $source_tap = $!source.tap( -> \val {
-                      @batched.push: val;
-                      flush if @batched.elems == $!elems;
-                  },
-                  done => {
-                      flush if @batched;
-                      self!done();
-                  },
-                  quit => -> $ex { self!quit($ex) });
-                $tap
+                {
+                    more => -> \val {
+                        @batched.push: val;
+                        flush if @batched.elems == $elems;
+                    },
+                    done => {
+                        flush if @batched;
+                        $res.done;
+                    }
+                }
             }
         }
-        RotorSupply.new(:source($s), :$elems, :$overlap)
     }
 
     method batch(Supply $s, :$elems, :$seconds ) {