sub get_keyword_names {
    my ($self) = @_;
    my $class = $self->lib;
    my @methods = Class::Inspector->methods( $class, 'public' );
    return \@methods;
}

sub run_keyword {
   my $self = shift;
   my ($stdout, $stderr) = capture { ... };
}
sub start_server {
    my $self = shift;
    $self->backend->start_server;
}

##</code><code>##

package RobotRemoteServer::Frontier;
sub _shut_down_request {
RobotRemoteServer::Frontier
sub start_server {
  my ($self) = @_;
  my $svr = Frontier::Daemon->new(
    methods => {
      get_keyword_names => sub { $self->get_keyword_names(@_) },
      run_keyword => sub { $self->run_keyword($_[0], eval{@{$_[1]}}) },
      stop_remote_server => sub {
          $srv->_shutdown('yes please');
          $self->schedule_shutdown;
          return;
      },
    ....
}

sub schedule_shutdown {
    my $self = shift;
    my $url = $self->url;
    if( eval { require threads; } ){
        threads::async {
           sleep 5;
           require Frontier::Client;
           Frontier::Client->new( 'url' => $url )->call('stop_remote_server');
        };
    } elsif( eval { require Proc::Background; } ){
        Proc::Background->new(
            $^X,
            '-e', q{
use Frontier::Client;
sleep 5;
my $url = shift @ARGV;
Frontier::Client->new( 'url' => $url )->call('stop_remote_server');
exit;       },
            $url,
        );
    }
}
sub Frontier::Daemon::_shutdown {
    my( $self, $true ) = @_;
    ${*$self}{'_Frontier::Daemon::_shutdown'} = !!$true if $true; 
    return ${*$self}{'_Frontier::Daemon::_shutdown'} ;
}

sub Frontier::Daemon::accept { ## monkeypatch
    package Frontier::Daemon;
    my $self = shift;
    if( $self->_shutdown ){
        close $self;
        return;
    } else {
        return $self->SUPER::accept;
    }
}

##</code><code>##

use RobotRemoteServer;
#my $rob = RobotRemoteServer->new (qw' host localhost port 666  ');
my $rob = RobotRemoteServer->new (qw'
  host    localhost 
  port    666 
  backend Frontier
  lib     ExampleLibrary
');
$rob->start_server;