Using a different content type for files

By default, the mime module is used to automatically map file extensions to a mime type.
If you're finding your files get served with a incorrect content type, you can simply use the params field in the configuration to override this:

params: {
    '*.pdf': {
        ContentType: 'application/x-pdf'
    }
}

Remember: params that are configured by you will always override params that the plugin itself sets.