code: func (i *MintedTokenInfo) toBigQueryMessage() *bqpb.MachineToken {
  	// LUCI_MACHINE_TOKEN is the only supported type currently.
  	if i.Request.TokenType != tokenserver.MachineTokenType_LUCI_MACHINE_TOKEN {
  		panic("unknown token type")
  	}
  	return &bqpb.MachineToken{
  		// Identifier of the token body.
  		Fingerprint: utils.TokenFingerprint(i.Response.GetLuciMachineToken().MachineToken),
  
  		// Information about the token.
  		MachineFqdn:        i.TokenBody.MachineFqdn,
  		TokenType:          i.Request.TokenType,
  		IssuedAt:           &timestamp.Timestamp{Seconds: int64(i.TokenBody.IssuedAt)},
  		Expiration:         &timestamp.Timestamp{Seconds: int64(i.TokenBody.IssuedAt + i.TokenBody.Lifetime)},
  		CertSerialNumber:   fmt.Sprintf("%d", i.TokenBody.CertSn),
  		SignatureAlgorithm: i.Request.SignatureAlgorithm,
  
  		// Information about the CA used to authorize this request.
  		CaCommonName: i.CA.CN,
  		CaConfigRev:  i.CA.UpdatedRev,
  
  		// Information about the request handler.
  		PeerIp:         i.PeerIP.String(),
  		ServiceVersion: i.Response.ServiceVersion,
  		GaeRequestId:   i.RequestID,
  	}
  }
docs: // toBigQueryMessage returns a message to upload to BigQuery.