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# Publishers.SubscribeOn

A publisher that receives elements from an upstream publisher on a specific scheduler.

```
struct SubscribeOn<Upstream, Context> where Upstream : Publisher, Context : Scheduler
```

## Topics

### Creating a subscribe-on publisher

[`init(upstream: Upstream, scheduler: Context, options: Context.SchedulerOptions?)`](/documentation/Combine/Publishers/SubscribeOn/init(upstream:scheduler:options:))

Creates a publisher that receives elements from an upstream publisher on a specific scheduler.

### Declaring supporting types

[`typealias Output`](/documentation/Combine/Publishers/SubscribeOn/Output)

The kind of values published by this publisher.

[`typealias Failure`](/documentation/Combine/Publishers/SubscribeOn/Failure)

The kind of errors this publisher might publish.

### Inspecting publisher properties

[`let upstream: Upstream`](/documentation/Combine/Publishers/SubscribeOn/upstream)

The publisher from which this publisher receives elements.

[`let scheduler: Context`](/documentation/Combine/Publishers/SubscribeOn/scheduler)

The scheduler the publisher should use to receive elements.

[`let options: Context.SchedulerOptions?`](/documentation/Combine/Publishers/SubscribeOn/options)

Scheduler options that customize the delivery of elements.

## Relationships

### Conforms To

[`Publisher`](/documentation/Combine/Publisher)

---

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