---
title: "StageObserver"
sidebar_label: "StageObserver"
description: "Kotlin binding reference: StageObserver."
---

<!-- Generated by tools/api_reference/generate_api_docs.py. Do not edit. -->

//[clika-runtime](../../../index.md)/[io.clika.modelverse](../index.md)/[StageObserver](index.md)

# StageObserver

[common]\
fun interface [StageObserver](index.md)

Hears a model's pipeline stages ([GenerativeModel.setStageObserver](../GenerativeModel/setStageObserver.md), or one call's through [GenerativeModel.generate](../GenerativeModel/generate.md)). [onStage](onStage.md) runs on the stage's own thread, never the caller's, and must return at once: a slow observer holds that stage and nothing else. An exception it lets escape goes to its thread's uncaught-exception handler.

## Functions

| Name | Summary |
|---|---|
| [onStage](onStage.md) | [common]<br>abstract fun [onStage](onStage.md)(event: [StageEvent](../StageEvent/index.md)) |