function save(modelName, projectId, map = false, concurrency = 10) {
        return new Promise((resolve, reject) => {
            if (!this.stream) {
                return reject(new Error(`${modelName} import error: no stream present!`));
            }

            map = map.length ? map : p21map[modelName];

            this.stream.pipe(pressure(function (data, cb) {
                const row = { projectId: projectId };
                const val = Object.values(data);

                if (map.length !== val.length) {
                    return cb(new Error(`${modelName} import error: map.length != val.length`));
                }

                // map data (val) to row using map
                for (let i = 0; i < map.length; i++) {
                    row[map[i]] = val[i].length ? val[i] : null;
                }

                db[modelName].create(row)
                .then(() => cb())
                .catch(function (err) {
                    db.ImportError.create({
                        projectId : projectId,
                        model     : modelName,
                        data      : JSON.stringify(row),
                        error     : JSON.stringify(err) // JSON.stringify(err.errors)
                    });

                    cb();
                });
            }, concurrency));

            this.stream.on('end', resolve);
            this.stream.on('error', reject);
            this.stream.resume();
        });
    }