closeConnOnce := &sync.Once{}
	closeConn := func() {
		closeConnOnce.Do(func() {
			ws.Close()
		})
	}

	negotiated := ws.Config().Protocol
	r.selectedProtocol = negotiated[0]
	defer close(r.err)
	defer closeConn()

	go func() {
		defer runtime.HandleCrash()
		// This blocks until the connection is closed.

type grpcCall struct {
	e       *executor
	getConn grpcConnectionGetter
}

func (c *grpcCall) makeRequest(ctx context.Context, cfg *Config, requestID int) (string, error) {
	conn, closeConn, err := c.getConn()
	if err != nil {
		return "", err
	}
	defer closeConn()

	// Set the per-request timeout.
	ctx, cancel := context.WithTimeout(ctx, cfg.timeout)
	defer cancel()

	// Add headers to the request context.