aysynchronous Rx Observable test handle function

XCTRxHandle

public func XCTRxHandle<Element>(_ description: String = "XCTAssertForRx", testcase: XCTestCase, timeout: TimeInterval = 1, queue: DispatchQueue = DispatchQueue(label: "Rx queue"), observable: Observable<Element>, trigger: @autoclosure @escaping () -> Void = {}(), value onNext: @escaping (Element?) -> Void = { _ in }, completed: @autoclosure @escaping () -> Void = {}(), error onError: @escaping (Error?) -> Void = { _ in }, result: (XCTWaiter.Result) -> Void = { _ in } ) {
	let expect = testcase.expectation(description: description)
	expect.assertForOverFulfill = false
	let bag = DisposeBag()
	queue.async {
		observable.subscribe({ (event) in
			switch event {
			case .error(let error):
				onError(error)
				onNext(nil)
				expect.fulfill()
			case .next(let element):
				onNext(element)
				onError(nil)
				expect.fulfill()
			case .completed:
				completed()
				onError(nil)
				expect.fulfill()
			}
		}).disposed(by: bag)
	}
	queue.async {
		trigger()
	}
	result(XCTWaiter.wait(for: [expect], timeout: timeout))
}