https://github.com/ReactiveX/RxSwift/blob/d158e7700655114e990313948d2de561d50e1115/RxSwift/Schedulers/ConcurrentMainScheduler.swift#L13-L19

/** Abstracts work that needs to be performed on `MainThread`. In case `schedule` methods are called from main thread, it will perform action immediately without scheduling. This scheduler is optimized for `subscribeOn` operator. If you want to observe observable sequence elements on main thread using `observeOn` operator, `MainScheduler` is more suitable for that purpose. */

ReactiveX/RxSwift

Reactive Programming in Swift. Contribute to ReactiveX/RxSwift development by creating an account on GitHub.