immediateFire not work

[dourgulf]

for such testcase

    func test_throttleFirstImmediateFire() {
        let exp = expectation(description: "Run twice and call immediately")

        var value = 0
        let extractedExpr = Throttler(time: .milliseconds(500), immediateFire: true, {
            value += 1
        })
        self.throttle = extractedExpr

        self.throttle?.call()
        self.throttle?.call()
        self.throttle?.call()
        self.throttle?.call()
        self.throttle?.call()

        DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(1)) {
            if value == 2 {
                exp.fulfill()
            } else {
                XCTAssert(value == 2, "Failed to throttle, calls were not ignored.")
            }
        }

        self.wait(for: [exp], timeout: 1)
    }

expect value == 2, first time and second time after 500ms.
but, this test case failed,
I guess
queue.asyncAfter(deadline: dispatchTime, execute: callbackJob) was cancel by second call()