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# AVMetricEventStream

An object that allows clients to add publishers and then subscribe to specific metric event classes from those publishers.

```
@interface AVMetricEventStream : NSObject
```

## Overview

Publishers are [`AVFoundation`](/documentation/AVFoundation) types that adopt [`AVMetricEventStreamPublisher`](/documentation/AVFoundation/AVMetricEventStreamPublisher). The protocol allows clients to receive metric events with a subscriber delegate which adopts the [`AVMetricEventStreamSubscriber`](/documentation/AVFoundation/AVMetricEventStreamSubscriber) protocol.

## Topics

### Getting the event stream

[`eventStream`](/documentation/AVFoundation/AVMetricEventStream/eventStream)

### Adding a publisher

[`addPublisher:`](/documentation/AVFoundation/AVMetricEventStream/addPublisher:)

### Subscribing to events

[`subscribeToAllMetricEvents`](/documentation/AVFoundation/AVMetricEventStream/subscribeToAllMetricEvents)

[`subscribeToMetricEvent:`](/documentation/AVFoundation/AVMetricEventStream/subscribeToMetricEvent:)

[`subscribeToMetricEvents:`](/documentation/AVFoundation/AVMetricEventStream/subscribeToMetricEvents:)

### Setting a subscriber

[`setSubscriber:queue:`](/documentation/AVFoundation/AVMetricEventStream/setSubscriber:queue:)


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