How DelegateProxy works in RxSwift?
DelegateProxy is a core feature in Rxswift to wrap the return value from original delegate to observable sequence. So it's important to discover how it works in RxSwift. Under the hood, message forwarding, a feature in Objective-C, plays a role in forwarding message from proxy to real delegate. You should have some basic knowledges about Objective-C Runtime before you go deeper. You can learn that in this post (Chinese version): Objective-C Runtime详解.