code: func checkChainTrustStatus(c *Certificate, chainCtx *syscall.CertChainContext) error {
  	if chainCtx.TrustStatus.ErrorStatus != syscall.CERT_TRUST_NO_ERROR {
  		status := chainCtx.TrustStatus.ErrorStatus
  		switch status {
  		case syscall.CERT_TRUST_IS_NOT_TIME_VALID:
  			return CertificateInvalidError{c, Expired}
  		default:
  			return UnknownAuthorityError{c, nil, nil}
  		}
  	}
  	return nil
  }
docs: // checkChainTrustStatus checks the trust status of the certificate chain, translating
  // any errors it finds into Go errors in the process.