# Combine \`.receive(on: RunLoop.main)\` loses sent value. How can I make it work?

**URL:** <https://forums.swift.org/t/combine-receive-on-runloop-main-loses-sent-value-how-can-i-make-it-work/28631>\
**Category:** Using Swift\
**Tags:** combine\
**Created:** [September 8, 2019, 1:27pm UTC](https://forums.swift.org/t/combine-receive-on-runloop-main-loses-sent-value-how-can-i-make-it-work/28631 "2019-09-08T13:27:35Z")\
**Posts on this page:** 1\
**Showing post:** 39

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**Author:** ![Tony\_Parker](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/tony_parker/32/273_2.png) [@Tony\_Parker](https://forums.swift.org/u/Tony_Parker)\
**Post date:** [November 6, 2019, 4:35am UTC](https://forums.swift.org/t/combine-receive-on-runloop-main-loses-sent-value-how-can-i-make-it-work/28631/39 "2019-11-06T04:35:46Z")

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Hello all,

As of developer beta 1 of iOS 13.3 (and associated releases for other platforms), we've changed the behavior of `receive(on:)` plus other `Scheduler` operators to synchronously send their subscription downstream. Previously, they would "async" it to the provided scheduler.

This means that the test case in the original post of this thread now does what most would expect (print the value). Since the subscription is received synchronously by `sink`, and it synchronously requests `.unlimited` from its upstream, there is no opportunity for any values sent to the `PassthroughSubject` to be dropped.

If you have access to the developer betas, please give it a try with your own Combine scenarios and let me know how it goes.

I'd like to extend a special thank you to everyone here and elsewhere across the web who provided us valuable feedback on this.

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