Always present for WebhookRequest. Ignored for WebhookResponse. The unique identifier of the current page. Format: projects/<Project ID>/locations/<Location ID>/agents/<Agent
ID>/flows/<Flow ID>/pages/<Page ID>.
Always present for WebhookRequest. Required for WebhookResponse. The human-readable name of the parameter, unique within the form. This field cannot be modified by the webhook.
Optional for both WebhookRequest and WebhookResponse. Indicates whether the parameter is required. Optional parameters will not trigger prompts; however, they are filled if the user specifies them. Required parameters must be filled before form filling concludes.
Always present for WebhookRequest. Required for WebhookResponse. The state of the parameter. This field can be set to INVALID by the webhook to invalidate the parameter; other values set by the webhook will be ignored.