Another rakudo issue

clog.p6

#!/usr/bin/env perl6
my $out = Channel.new;
#my $proc = Proc::Async.new(‘perl6’, ‘-e’, ‘sleep ∞’); # this works
my $proc = Proc::Async.new(‘perl6’, ‘-e’, ‘.say for 0..0x1FFFF’); # ← this doesn't
$proc.stdout.tap({ $out.send: 1 });

my $promise = $proc.start;
say ‘let's await  ’, now;
await Promise.anyof(Promise.in(1), $promise);
say ‘let's close  ’, now;
$proc.kill;
await $promise;
$out.close;
say ‘that's it    ’, now;