Document order in which handlers get applied

[oalders]

From my testing it appears to be:

request_preprepare
request_prepare
request_send
response_header
response_data
response_done
response_redirect

See:

use strict;
use warnings;
use feature qw( say );

use LWP::UserAgent;
my $ua = LWP::UserAgent->new; 

my @phases = (
    'request_preprepare',
    'request_prepare',
    'request_send',
    'response_header',
    'response_data',
    'response_done',
    'response_redirect',
  );

for my $phase (@phases) {   
    $ua->add_handler( $phase => sub { say "$phase"; return undef; } );
}

$ua->get('https://metacpan.org');