code: func getBuf(size int) []byte {
  	if size < config.PooledSize {
  		return make([]byte, 0, size)
  	}
  
  	if c := buffers[size]; c != nil {
  		v := c.Get()
  		if v != nil {
  			return v.([]byte)
  		}
  	}
  	return make([]byte, 0, size)
  }
docs: // getBuf gets a chunk from reuse pool or creates a new one if reuse failed.