Method start

guava/src/com/google/common/base/Stopwatch.java:163–169

Starts the stopwatch. @return this {@code Stopwatch} instance @throws IllegalStateException if the stopwatch is already running.

()

   * @throws IllegalStateException if the stopwatch is already running.
   */
  @CanIgnoreReturnValue
  public Stopwatch start() {
    checkState(!isRunning, "This stopwatch is already running.");
    isRunning = true;
    startTick = ticker.read();
    return this;
  }

  /**
   * Stops the stopwatch. Future reads will return the fixed duration that had elapsed up to this