新增于: v12.12.0
异步地关闭目录的底层资源句柄。
后续读取将导致错误。
返回将在资源关闭后解决的 promise。
Added in: v12.12.0
Asynchronously close the directory's underlying resource handle.
Subsequent reads will result in errors.
A promise is returned that will be resolved after the resource has been
closed.