Email::__construct( string $event, array $args = array() )

	public function __construct( $event, $args = [] ) {
		$this->event = $event;

		$this->args = wp_parse_args( $args, array(
			'users'             => [],
			'subject'           => '',
			'tags'              => 	array(
				'site_name'        => get_bloginfo( 'name' ),
				'site_url'         => get_bloginfo( 'url' ),
				'site_description' => get_bloginfo( 'description' ),
			),
			'template'          => [],
			'headers'           => array(
				'Content-Type: text/html; charset=utf-8',
			),
		) );

		$this->email_headers = $this->args['headers'];
		unset( $this->args['headers'] );

		// Add template tags.
		if ( ! empty( $this->args['tags'] ) ) {
			foreach ( $this->args['tags'] as $tag => $content ) {
				$this->add_template_tag( $tag, $content );
			}
		}
	}