Swift3 DispatchSourceTimer

Swift3_timer2.swift

//: Playground - noun: a place where people can play

import Cocoa

var str = "Hello, playground"

import Foundation
import Dispatch

func test(){
    for _ in 1..<5 {
        print("\(Date()) Hello, World!")
    }
}

class testclass{
    typealias qblock = ((DispatchSourceTimer) ->Void)
    let call:qblock
    var dispatch_timer:DispatchSourceTimer
    let q :DispatchQueue
    init(c:@escaping qblock) {
        call = c
         q = DispatchQueue(label:"com.fb.interview")
        self.dispatch_timer =  DispatchSource.makeTimerSource(flags: DispatchSource.TimerFlags.init(rawValue: 0), queue:q )
        q.async{
            let interval: Double = 1.0
            
            let delay = DispatchTime.now()
            
            self.dispatch_timer.scheduleRepeating(deadline: delay, interval: interval, leeway: .nanoseconds(0))
            
            self.dispatch_timer.setEventHandler {
                
                self.call(self.dispatch_timer)
            }
            self.dispatch_timer.setCancelHandler {
                print("dispatch_timer cancel")
            }
            self.dispatch_timer.resume()
            
        }
    }
    func resume() {
        q.async {
            self.dispatch_timer.resume()
        }
    }
    
}
var begin = Date()
class FBClass{
    var fbTimer:testclass
    
    init(){
        
        fbTimer = testclass.init {(t:DispatchSourceTimer) in
            if  Date().timeIntervalSince(begin) > 10{
                print(t.suspend())
                print("\(Date()) cancel")
                begin = Date()
                return
            }
            
            print("\(Date()) working")
        }
    }
    func resume() {
        fbTimer.dispatch_timer.resume()
    }
}

let fbTest = FBClass()
for i in 0...50 {
    //main don't exit
    sleep(1)
    if i == 15 {
       fbTest.resume()
    }
    //usleep(5000)
}