Rxswift: use asSingle()

[Z-JaDe]

let a = PublishSubject()
a.asSingle().subscribe(onSuccess: { (_) in
print("asasaa")
}) { (error) in

}.disposed(by: self.disposeBag)
a.onNext(1)

When I call the code above, there is no print.
Is the asSingle() method using errors?

[Z-JaDe]

I looked at the code for asSingle() ,
found that I needed to send it myself (. Completed)
So I added take(1) in front of asSingle()

[berikv]

It is required to call take(1) on PublishSubject before calling asSingle:

let subject = PublishSubject<Void>()
subject
    .take(1) // Without `take(1)` there is no success event
    .asSingle()
    .subscribe(onSuccess: { print("success") }, onError: nil)
subject.onNext(())

This is unexpected and may cause bugs.

[jokerYellow]

I looked at the code for asSingle() ,
found that I needed to send it myself (. Completed)
So I added take(1) in front of asSingle()

great! save my time