Helpful tool for printing to console when you are trying to figure out what is taking so long

Stopwatch.swift

class Stopwatch {
    static let shared = Stopwatch()

    let name: String
    var shouldLogInRealTime: Bool = false

    private var start: Date? {
        willSet {
            lap = newValue
        }
    }
    private var lap: Date?
    private var printLines: [String] = []
    
    init(named name: String = "") {
        self.name = name
    }

    func markStart() {
        printLines = []
        start = Date()
        let name = self.name.isEmpty
            ? "SHARED"
            : "\"\(self.name)\""
        printOut("\n\n**************** \(name) STOPWATCH STARTED ****************\n")
    }

    func markLap(named: String = "") {
        guard let lap = lap else {
            printOut("!!!!!!! STOPWATCH ERROR !!!!!!!")
            printOut("(- 0u0)- You forgot to start the Stopwatch first you big silly\n")
            return
        }
        let now = Date()
        let timePassed = now.timeIntervalSince(lap)
        let timeString = String(format: "%.5f", timePassed)
        printOut("    LAP: \(timeString) sec. (\(named))")
        self.lap = now
    }

    func markStop(andPrintSummary shouldPrint: Bool = false) {
        guard let start = start else {
            printOut("!!!!!!!!!!!!!! STOPWATCH ERROR !!!!!!!!!!!!!!")
            printOut("(- 0u0)- You forgot to start the Stopwatch first you big silly\n")
            return
        }
        let now = Date()
        let timePassed = now.timeIntervalSince(start)
        let timeString = String(format: "%5f", timePassed)
        printOut("\n    TOTAL: \(timeString) sec.")

        self.start = nil
        printOut("\n**************** STOPWATCH STOPPED ****************\n\n")

        if shouldPrint {
            printSummary()
        }
    }

    func printSummary() {
        for line in printLines {
            print(line)
        }
    }

    private func printOut(_ line: String) {
        if shouldLogInRealTime {
            print(line)
        }
        printLines.append(line)
    }
}