dispatch after calss swift3

dispatch_after_calss.swift

import Cocoa

var str = "Hello, playground"

let x = UINT32_MAX

class FBQueue {
    typealias qblock = ((Void) ->Void)
    typealias qfinishBlock = ((Bool) ->Void)?
    let call:qblock
    let q = DispatchQueue.init(label: "test", qos: .background, attributes: .init(rawValue: 0), autoreleaseFrequency: .never, target: nil)

    let callBack:qfinishBlock
    var cancle:Bool = false
    init(c:@escaping qblock, commpulte:qfinishBlock,after:DispatchTime) {
        call = c
        callBack = commpulte
        q.asyncAfter(deadline: after) {
            if self.cancle {
                self.callBack!(self.cancle)
            }else {
                self.call()
                self.callBack!(self.cancle)
               
            }
            
        }
    }
}
let sfQ = FBQueue.init(c: {
    print("execute")
}, commpulte: { (cancel:Bool) in
    if cancel {
        print("cancel")
    }
}, after: .now() + 3 )
print(Date())


for i in 0 ..< 100 {
    print(Date())
    sleep(1)
    if i == 2 {
        sfQ.cancle = true
    }
}