VersionID    string            `json:"versionId,omitempty"`
	Sequencer    string            `json:"sequencer"`
}

// Metadata represents event metadata.
type Metadata struct {
	SchemaVersion   string `json:"s3SchemaVersion"`
	ConfigurationID string `json:"configurationId"`
	Bucket          Bucket `json:"bucket"`
	Object          Object `json:"object"`
}

		EventName:         args.EventName,
		UserIdentity:      event.Identity{PrincipalID: args.ReqParams["principalId"]},
		RequestParameters: args.ReqParams,
		ResponseElements:  respElements,
		S3: event.Metadata{
			SchemaVersion:   "1.0",
			ConfigurationID: "Config",
			Bucket: event.Bucket{
				Name:          args.BucketName,
				OwnerIdentity: event.Identity{PrincipalID: args.ReqParams["principalId"]},