The first thing I notice is that there are things wrong with the code you've posted.

You have use strict; but $thread is never declared?

Also, you are attempting to start 200 threads, but only waiting for one to complete.

Try this:

#! perl -slw
use strict;
use threads ( stack_size => 4096 );
use threads::shared;
use LWP::Simple;
use Time::HiRes qw[ time sleep ];

our $T ||= 200;

my $url = ### your url (of the actual file!) here ###;

my $running :shared = 0;
my $start = time;

for( 1 .. $T ) {
    async(
        sub{
            { lock $running; ++$running };
            sleep 0.001 while $running < $T;
            my $id = shift;
            getstore( $url, qq[c:/test/dl.t.$id] );
            --$running;
        }, $_
    )->detach;
}

sleep 1 while $running;

printf "Took %.3f seconds\n", time() - $start;
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