why does this consume 1 CPU at 99% and 5GB RES mem?

fswatch-rsync.p6

#!/usr/bin/env perl6
use lib "{$?FILE.IO.dirname}/../lib".IO.resolve.path;
use Config;
sub MAIN (Str :$want   = '', Bool :$dry-run = False, Bool :$run-once = False) {
  chdir $LOCAL_SRC_DIR or die "Error directory not found $LOCAL_SRC_DIR";
  my $fswatch-channel   = Channel.new;
  my $rsync-channel     = Channel.new;
  my $loop-promise      = Promise.new;
  my @app-dirs          = find-app-dirs($want);
  my $rsync_count       = @app-dirs.elems - 1;
  Promise.in(3).then({
    for @app-dirs -> [$API, $basedir, $dir] {
      $rsync-channel.send([$API, $basedir, $dir]);
    }
  });
  react {
    whenever $fswatch-channel -> [$API, $basedir, $dir] {
      my $fswatch = Proc::Async.new("fswatch","-1","--exclude=.git","-r","-l 1",$dir,:cwd($dir));
      $fswatch.stdout.act: -> $line {
        print "fswatch changed {$line}".dark-pink;
        $rsync-channel.send([$API, $basedir, $dir]);
      };
      $fswatch.start;
    }
    whenever $rsync-channel -> [$API, $basedir, $dir] {
      my $exclude = "{$HOME}/.rsync-exclude-{$API}".IO.f ?? "{$HOME}/.rsync-exclude-{$API}" !! "{$HOME}/.rsync-exclude";
      my $from    = "{$dir}/";
      my $to      = "{$REMOTE_HOST}:{$REMOTE_SRC_DIR}/{$basedir}/{$REMOTE_SUFFIX}";
      say "rsync {($dry-run ?? 'dry-run' !! '')}".mid-blue;
        {($dry-run ?? "dry-run" !! "")}
      print qq:to/TXT/.mid-pink;
        exclude {$exclude}
        from    {$dir}
        to      {$to}
      TXT
      my $rsync = Proc::Async.new("rsync", "-ai"~($dry-run ?? "n" !! ""), "-e'ssh'", "--delete", "--exclude-from=$exclude", $from, $to, :cwd($dir), :out, :err);
      $rsync.stderr.act: -> $line { print $line.dark-blue };
      $rsync.stdout.act: -> $line { print $line.mid-blue  };
      await $rsync.start;
      if $run-once {
        if $rsync_count-- == 0 {
          $loop-promise.keep("run-once done");
        }
      } else {
        $fswatch-channel.send([$API, $basedir, $dir]);
      }
    }
  }
  loop { 
    if $loop-promise.status !~~ Planned {
      last;
    }
  }
  say $loop-promise.result.dark-red;
}