use IPC::Open3 qw( open3 );

my @tail_pids;

END {
   for my $tail_pid (@tail_pids) {
      kill TERM => $tail_pid;
      waitpid($tail_pid, 0);
   }
}

sub start_tail {
   my ($mw, $file) = @_;

   my ($from_tail, $tail_err);
   push @tail_pids, open3(undef, $from_tail, $tail_err, qw( tail -1lf ), $file);

   $mw->fileevent($from_tail, 'readable' => [ \&input_from_tail, $mw, $file ]);
   $mw->fileevent($tail_err,  'readable' => [ \&sink,            $mw, $file ]);
}