var net/http.ErrNotSupported

7 uses

	net/http (current package)
		http2.go#L183: 		err = ErrNotSupported
		request.go#L56: 	return pe == ErrNotSupported && err == errors.ErrUnsupported
		request.go#L66: 	ErrNotSupported = &ProtocolError{"feature not supported"}
		responsecontroller.go#L146: 	return fmt.Errorf("%w", ErrNotSupported)
		server.go#L4129: 	return ErrNotSupported
		transport.go#L2818: 	return fmt.Errorf("CloseWrite: %w", ErrNotSupported)

	net/http/httputil
		reverseproxy.go#L842: 	if errors.Is(hijackErr, http.ErrNotSupported) {