// whether they client has sent exactly one (non-CA) leaf certificate.
	peerCertificates := make([]*x509.Certificate, 0, len(r.TLS.PeerCertificates))
	for _, cert := range r.TLS.PeerCertificates {
		if cert.IsCA {
			continue
		}
		peerCertificates = append(peerCertificates, cert)
	}
	r.TLS.PeerCertificates = peerCertificates

	// Now, we have to check that the client has provided exactly one leaf