static getInstance(progressCallback = null) {
        if (this.task === null || this.model === null) {
            throw Error("Must set task and model")
        }
        if (this.instance === null) {
            this.instance = pipeline(this.task, this.model, {
                progress_callback: progressCallback
            });
        }

        return this.instance;
    }
Get pipeline instance
@param {*} progressCallback 
@returns {Promise}