# Receiver:
my $data = do {
   my $length = do {
      my $buf;
      sysread( $sock, $buf, 4-length($buf), length($buf) )
         while length($buf) < 4;
      unpack( 'N', $buf )
   };

   my $buf;
   sysread( $sock, $buf, $length-length($buf), length($buf) )
      while length($buf) < $length;
   deserialize($buf)
};