use strict;
use warnings;
use AnyEvent;
use AnyEvent::Strict;

open(my $fh, '<', 'C:/Temp/TestFile.txt') or die $!;
my $done    = AnyEvent->condvar;
my $watcher 
    = AnyEvent->io
        ( fh   => $fh
        , poll => 'r'
        , cb   => 
            sub {
                my $input = <$fh>;
                print "Input [$input]\n";
                if ( $input =~ /^End of processing file/ ) {$done->send; }
            }
    );
$done->recv;
close $fh or die $!;
print "All done!\n";