single_fail.swift

let single = Single<Int>.error(SomeError())

// AS IS
single.subscribe(onSuccess: { value in
    print("Got a value:", value)
}, onFailure: { error in
    print("Got a error:", error)
}, onDisposed: {

}).disposed(by: disposeBag)
// Prints
Got a error: SomeError()


// TO BE 
Task {
    do {
        let value = try await single.value
        print("Got a value:", value)
    } catch {
        print("Got a error:", error)
    }
}
// Prints
Got a error: SomeError()