async function test() {
  const filename = 'freyr_mgr_temp_file';
  async function testMgr(args) {
    const file = await genFile({filename, ...args}).read();
    console.log('mgr>', file);
    return file;
  }
  let a = await testMgr();
  let b = await testMgr();
  let _c = await testMgr({keep: true});
  let d = await testMgr();
  a.remove();
  b.remove();
  // _c.remove(); // calling this would negate the keep directive
  d.remove();
}
File will be written to once, unless forcefully forgotten.