WordPress::Create custom static page on custom url

init-custom-download-page.php

<?php

add_action('init', 'create_download_page');
public function create_download_page() {
	global $wp;
	$home_url = network_home_url();
	$download_url = trailingslashit(network_home_url('download'));
	
	// current url path
	$current_path = parse_url(add_query_arg(array()), PHP_URL_PATH);
	$current_path = trailingslashit($current_path);

	// get the strpos & substr
	$pos = strripos($download_url, $current_path);
	$substr = substr($download_url, 0, $pos);

	// is all true?
	$is_pos = ($pos !== false);
	$is_last_segment = ($is_pos && ($substr . $current_path) == $download_url);
	$is_include_home_url = ($is_pos && strlen($home_url) > $pos);

	// load the download file if true
	if($is_pos && $is_last_segment && $is_include_home_url) {
     		require_once(plugin_dir_path( __FILE__ ) . 'download-page.php');
     		exit();
  	}
}