Remember the example_open() function and its usage: 

<?php
$fp = example_open("/path/to/file");
fwrite($fp, "hello there\n");
rewind($fp);
echo fgets($fp);
?>
We can now use the example:// protocol scheme to access our custom streams via fopen(), include(), readfile() copy() etc. 

<?php
$fp = fopen("example:///path/to/file");
fwrite($fp, "hello there\n");
rewind($fp);
echo fgets($fp);
?>