my $Qstdin = new Thread::Queue;
async {
    $Qstdin->enqueue( $_ ) while defined( $_ = <STDIN> );
}->detach;

...

while( 1 ) {
    if( my @readers = $selector->can_read( 0.1 ) ) {
        ## See what they have to say
    }
    elsif( my @writers = $selector->can_write( 0.1 ) {
        ## Tell'em what they need to know
    }
    elsif( my @exceptors = $selector->has_exception( 0.1 ) {
        ## Deal with their tantrums
    }
    else {
        while( $Qstdin->pending ) {
            my $kbinput = $Qstdin->dequeue;
            ## do whatever
        } 
    }
}