我应该如何在composer包中包含XML数据文件？

I'm working on a PHP library (as a composer package) that needs a XML file to work. I'm using simplexml_load_file to load the XML file, but I'm wondering where I should put the file and how to get a path that always works. The current file structure looks like this is:

/
  src/
    Vendor/
      Library.php
  tests/
    LibraryTest.php
  composer.json
  composer.lock

My composer.json file :

{
    "name": "vendor/library",
    "require": {
        "php": ">=5.3.0"
    },
    "autoload": {
        "psr-0": {
            "Vendor": "src/"
        }
    }
}

You can't do this directly, but there are some possibilities:

1. Create a private repository which will contain only your XML file and add it to your composer. You'll then find it in your vendor folder. Here you can find a documentation about how to create custom repos: https://getcomposer.org/doc/articles/handling-private-packages-with-satis.md

2. Save it in your application, in some data folder and add to a GIT.

3. Add a simple checking to your application, so if the XML file hasn't been found, display message with information how to get it.

I'd recommend to mix points 2 and 3.