my $stdout-tap;
my $proc = Proc::Async.new( 'perl', '-e', 'while (<>) { print STDERR "STDERR\n"; print "STDOUT\n"; }', :r, :w );

#$proc = Proc::Async.new( 'perl', $filename, :r, :w );
my $stdout = $proc.stdout;
$stdout-tap = $stdout.lines.tap( { say "got message!" } );
my $promise = $proc.start;
for ^100 {
	await $proc.say("Sending message....");
}
#$proc.close-stdin;
await $promise;