code: func (s *Stream) Shrink() {
  	s.recvLock.Lock()
  	if s.recvBuf != nil && s.recvBuf.Len() == 0 {
  		s.recvBuf = nil
  	}
  	s.recvLock.Unlock()
  }
docs: // Shrink is used to compact the amount of buffers utilized
  // This is useful when using Yamux in a connection pool to reduce
  // the idle memory utilization.