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# CustomCombineIdentifierConvertible

A protocol for uniquely identifying publisher streams.

```
protocol CustomCombineIdentifierConvertible
```

## Overview

If you create a custom [`Subscription`](/documentation/Combine/Subscription) or [`Subscriber`](/documentation/Combine/Subscriber) type, implement this protocol so that development tools can uniquely identify publisher chains in your app.
If your type is a class, Combine provides an implementation of [`combineIdentifier`](/documentation/Combine/CustomCombineIdentifierConvertible/combineIdentifier) for you.
If your type is a structure, set up the identifier as follows:

```
let combineIdentifier = CombineIdentifier()
```

## Topics

### Identifying publisher streams

[`combineIdentifier`](/documentation/Combine/CustomCombineIdentifierConvertible/combineIdentifier)

A unique identifier for identifying publisher streams.


---

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