gistfile1.go

type limitConn struct {
	mu sync.Mutex // only for closing the net.Conn
	net.Conn
}

func (lc *limitConn) Read(b []byte) (int, error) {
	lc.mu.Lock()
	defer lc.mu.Unlock()

	if lc.Conn == nil {
		return 0, nil // Silently ignore closed connection.
	}
	return lc.Conn.Read(b)
}

func (lc *limitConn) Close() error {
	lc.mu.Lock()
	defer lc.mu.Unlock()

	if lc.Conn == nil {
		// Silently ignore double close.
		return nil
	}
	err := lc.Conn.Close()
	lc.Conn = nil
	return err
}