let date_start = NSDate()

// Code to be executed

println("(-date_start.timeIntervalSinceNow)")

func testExample() {

    self.measureBlock() {
        //do something you want to measure
    }
}

func printTimeElapsedWhenRunningCode(title:String, operation:()->()) {
    let startTime = CFAbsoluteTimeGetCurrent()
    operation()
    let timeElapsed = CFAbsoluteTimeGetCurrent() - startTime
    println("Time elapsed for (title): (timeElapsed) s.")
}

func timeElapsedInSecondsWhenRunningCode(operation: ()->()) -> Double {
    let startTime = CFAbsoluteTimeGetCurrent()
    operation()
    let timeElapsed = CFAbsoluteTimeGetCurrent() - startTime
    return Double(timeElapsed)
}

printTimeElapsedWhenRunningCode(title:"map()") {
    let resultArray1 = randoms.map { pow(sin(CGFloat($0)), 10.0) }
}

import Foundation

func measure(_ title: String, block: (() -> ()) -> ()) {

    let startTime = CFAbsoluteTimeGetCurrent()

    block {
        let timeElapsed = CFAbsoluteTimeGetCurrent() - startTime
        print("(title):: Time: (timeElapsed)")
    }
}

measure("some title") { finish in
    myAsyncCall {
        finish()
    }
    // ...
}

measure("some title") { finish in
     // code to benchmark
     finish()
     // ...
}