You will need to read the Net::SNMP documentation several times before it sinks in properly, I found. Here's a quick example of how to get the IfInOctets and IfOutOctets for interface number 1 on multiple hosts in one hit. It's not much different from the examples in the docs, though:

use warnings;
use strict;
use Net::SNMP;

my $community="public";    # community string for devices
my $interface_number=1;    # interface number to poll
my @ip_addresses=("192.168.5.242","192.168.11.34");
# Queue up a request to each host.
foreach (@ip_addresses)
{
        my ($session,$error)=Net::SNMP->session(-hostname=>"$_",
            -nonblocking=>1,
            -community=>"$community",
            -timeout=>2,
            -retries=>3,
            );
    if (defined($session))
    {
        my $in_oid=".1.3.6.1.2.1.2.2.1.10."."$interface_number";    # 
+OIDs to poll.
        my $out_oid=".1.3.6.1.2.1.2.2.1.16."."$interface_number";
        my $uptime_oid=".1.3.6.1.2.1.1.3.0";
        my @oids=($in_oid,$out_oid,$uptime_oid);
        my $result=$session->get_request(
            -varbindlist=>\@oids,
            callback=>[\&reply,$interface_number,$_]
            );
    }
    else
    {
        print "Session not defined! $error\n";
    }
}
# All requests are queued. Now dispatch them.
snmp_dispatcher();
exit;
# Sub "reply" is executed for each response from remote hosts.
sub reply
{
    my $obj=shift;
    my $interface=shift;
    my $ip_address=shift;
    if (!defined($obj->var_bind_list))
    {
        warn "$ip_address SNMP Error.",$obj->error(),"\n";
        return;
    }
    my $in_oid=".1.3.6.1.2.1.2.2.1.10."."$interface";
    my $out_oid =".1.3.6.1.2.1.2.2.1.16."."$interface";
    my $uptime_oid=".1.3.6.1.2.1.1.3.0";
    my $uptime=$obj->var_bind_list->{$uptime_oid};
    my $in=$obj->var_bind_list->{$in_oid};
    my $out=$obj->var_bind_list->{$out_oid};
    print "$ip_address interface number $interface bytes in: $in bytes
+ out: $out Uptime $uptime\n";
}
[download]

Keep these things in mind when designing this:
In non-blocking mode, it will queue all requests without actually dispatching them until you execute the snmp_dispatcher.
At that point, your program will block until all requests have been finished.
Each time a response is recieved, it will call the 'reply' subroutine.
You only get control back to the main program after all requests have either completed or timed out.
Good luck.