filehandle.createWriteStream([options])

options 还可以包括 start 选项，以允许在文件开头的某个位置写入数据，允许的值在 [0, Number.MAX_SAFE_INTEGER] 范围内。 修改文件（而不是替换它）可能需要将 flags open 选项设置为 r+（而不是默认的 r）。 encoding 可以是 <Buffer> 接受的任何一种。

• options <Object>
  • encoding <string> Default: 'utf8'
  • autoClose <boolean> Default: true
  • emitClose <boolean> Default: true
  • start <integer>
• Returns: <fs.WriteStream>

options may also include a start option to allow writing data at some position past the beginning of the file, allowed values are in the [0, Number.MAX_SAFE_INTEGER] range. Modifying a file rather than replacing it may require the flags open option to be set to r+ rather than the default r. The encoding can be any one of those accepted by <Buffer>.

If autoClose is set to true (default behavior) on 'error' or 'finish' the file descriptor will be closed automatically. If autoClose is false, then the file descriptor won't be closed, even if there's an error. It is the application's responsibility to close it and make sure there's no file descriptor leak.

By default, the stream will emit a 'close' event after it has been destroyed. Set the emitClose option to false to change this behavior.