Quick stopwatch to do some basic timings in ruby

stopwatch.rb

#
# A simple stop watch for a quick timer to check app performance
#
# @see https://blog.dnsimple.com/2018/03/elapsed-time-with-ruby-the-right-way/
# 
# @example Basic Usage
#   timer = Stopwatch.new
#   timer.start   #=> 59539.814152996
#   timer.stop    #=> 59544.700881683
#   timer.elapsed #=> 4.886728687000868
#
class Stopwatch
  # Start the stopwatch.
  # 
  # @note this will clear the stopped time
  # 
  # @return [Float] The time started at
  def start
    @stopped = nil
    @started = current_time
  end

  # Get the time elapsed since start. 
  # 
  # @note this does not stop the timer
  #
  # @return [Float] The time since the timer was started
  def lap
    current_time - @started
  end

  # Stops the timer.
  #
  # @return [Float] The time stopped at
  def stop
    @stopped = current_time
  end

  # The amount of time between when the timer started and stopped.
  #
  # @note if the timer was never started then it will return the lap time
  # 
  # @return [Float]
  def elapsed
    (@stopped || current_time) - @started
  end

  # Reset the timer
  #
  # @return [void]
  def reset
    @started = nil
    @stopped = nil
  end

  private

  def current_time
    Process.clock_gettime(Process::CLOCK_MONOTONIC)
  end
end