wp_xmlrpc_server::add_enclosure_if_new( int $post_id, array $enclosure )

	public function add_enclosure_if_new( $post_ID, $enclosure ) {
		if ( is_array( $enclosure ) && isset( $enclosure['url'] ) && isset( $enclosure['length'] ) && isset( $enclosure['type'] ) ) {
			$encstring = $enclosure['url'] . "\n" . $enclosure['length'] . "\n" . $enclosure['type'] . "\n";
			$found = false;
			if ( $enclosures = get_post_meta( $post_ID, 'enclosure' ) ) {
				foreach ( $enclosures as $enc ) {
					// This method used to omit the trailing new line. https://core.trac.wordpress.org/ticket/23219
					if ( rtrim( $enc, "\n" ) == rtrim( $encstring, "\n" ) ) {
						$found = true;
						break;
					}
				}
			}
			if ( ! $found )
				add_post_meta( $post_ID, 'enclosure', $encstring );
		}
	}