generate a warning for an incorrect Content-Length header

gistfile1.pl

#!/usr/bin/env perl

use strict 'vars';
use warnings;

use Plack;
use Plack::Test::Agent;
use Socket;

my $server = 'Standalone';
my $app = sub { [ 200, [], ['hello, world'] ] };
my $agent = Plack::Test::Agent->new(
    app    => $app,
    server => $server,
);

# contact the server
open_tcp( F, $agent->host, $agent->port )
    or die 'Could not connect to server';

# Send request data
while ( my $request = <DATA> ) {
    print F $request;
}

# Get Response
while ( my $response = <F> ) {
    print "Response:> $response";
}

close( F );

# TCP Helper
sub open_tcp {

    # get parameters
    my ( $FS, $dest, $port ) = @_;

    my $proto = getprotobyname( 'tcp' );
    socket( $FS, PF_INET, SOCK_STREAM, $proto );
    my $sin = sockaddr_in( $port, inet_aton( $dest ) );
    connect( $FS, $sin );

    my $old_fh = select( $FS );
    $| = 1;    # don't buffer output
    select( $old_fh );
}

__DATA__
POST / HTTP/1.1
Content-Length:  10, 10

Foo Bar Baz
-END-