code: func (wp *WriterPool) Put(bw *bufio.Writer) {
  	// Should reset even if we do Reset() inside Get().
  	// This is done to prevent locking underlying io.Writer from GC.
  	bw.Reset(nil)
  	wp.pool.Put(bw, writerSize(bw))
  }
docs: // Put takes ownership of bufio.Writer for further reuse.