file.clone() break symlink

[GongT]

const VinylFile = require('vinyl')
const a = new VinylFile({stat: Object.assign(new fs.Stats, {mode: 41453}) , symlink: 'xxxx' })
console.log(a.symlink , a.isSymbolic())  // xxxx true
const b = a.clone()
console.log(b.symlink , b.isSymbolic())  // null true