gistfile1.txt

#!/usr/bin/perl6
use v6;

sub supply-capture-stdout (Supply $s, Callable $code) {
        my $count = 0;
  my $stdout = $*OUT;
  $*OUT = class {
    method print (*@args) {
      $s.emit(@args);
      $count++;
    }
    method flush () {}
  }
  $code.();
  $*OUT = $stdout;
  return $count;
}

my $string = "BEGIN\n"; 
my $out-supply = Supply.new();
my $sup-count = 0;
$out-supply.tap( -> $data { $sup-count++; $string ~= "$sup-count : Emitted $data\n"; });
my $count = supply-capture-stdout($out-supply, {
        my $ticker = Supply.interval(1);
        $ticker.tap( -> $sec { print $sec.WHICH , $sec; });
        sleep (5);
});     
$out-supply.close;
print "AFTER:\n$string";
print "COUNT: $count\t$sup-count";