src/Util/StreamFilter.php
public static function register()
    {
        if (self::$registered === null) {
            self::$registered = 'stream-callback';
            \stream_filter_register(self::$registered, CallbackFilter::class);
        }

        return self::$registered;
    }
public static function register()
    {
        if (self::$registered === null) {
            self::$registered = 'stream-callback';
            \stream_filter_register(self::$registered, CallbackFilter::class);
        }

        return self::$registered;
    }
public static function register ( ) { if ( self :: $ registered === null ) { self :: $ registered = 'stream-callback' ; \ stream_filter_register ( self :: $ registered , CallbackFilter :: class ) ; } return self :: $ registered ; }
registers the callback filter and returns the resulting filter name

There should be little reason to call this function manually.

@return string filter name
@uses CallbackFilter
registers the callback filter and returns the resulting filter name