# init(upstream:receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:) Creates a publisher that performs the specified closures when publisher events occur. ``` init(upstream: Upstream, receiveSubscription: ((any Subscription) -> Void)? = nil, receiveOutput: ((Publishers.HandleEvents.Output) -> Void)? = nil, receiveCompletion: ((Subscribers.Completion.Failure>) -> Void)? = nil, receiveCancel: (() -> Void)? = nil, receiveRequest: ((Subscribers.Demand) -> Void)?) ``` ## Parameters `upstream` The publisher from which this publisher receives elements. `receiveSubscription` A closure that executes when the publisher receives the subscription from the upstream publisher. `receiveOutput` A closure that executes when the publisher receives a value from the upstream publisher. `receiveCompletion` A closure that executes when the publisher receives the completion from the upstream publisher. `receiveCancel` A closure that executes when the downstream receiver cancels publishing. `receiveRequest` A closure that executes when the publisher receives a request for more elements. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)