#!/usr/bin/perl

use warnings;
use strict;
$|++;

use XML::LibXML;

my $parser = XML::LibXML->new();
my $closing_root_tag = '</ArgusFlowRecord>';
my $skip_past        = '<ArgusDataStream>';

{

  $XML::LibXML::skipXMLDeclaration = 1;

  local $/ = $skip_past;
  <>; # ignore declaration and stream open tag

  local $/ = $closing_root_tag;
  my $temp_chunk;

  while ( <> ) {
    $temp_chunk .= $_;
    my $dom;
    eval { $dom = $parser->parse_string( $temp_chunk ) };
    next if $@; # keep nibbling if XML is invalid
    undef $temp_chunk;
    print $dom->toString(), "\n"; # or do other processing
  }

}