* point.
   *
   * @return this {@code Stopwatch} instance
   * @throws IllegalStateException if the stopwatch is already stopped.
   */
  @CanIgnoreReturnValue
  public Stopwatch stop() {
    long tick = ticker.read();
    checkState(isRunning, "This stopwatch is already stopped.");
    isRunning = false;
    elapsedNanos += tick - startTick;
    return this;
  }

  /**

    public List<ModelProblem> getProblems() {
        return problems;
    }

    public void setSource(String source) {
        this.source = source;
        this.sourceModel = null;
    }

    public void setSource(Model source) {
        this.sourceModel = source;
        this.source = null;

        if (rootModel == null) {
            rootModel = source;
        }
    }

    private String getSource() {

    MockWebServer().apply {
      dispatcher = dispatcherB
    }

  /** This one won't start because it isn't annotated. */
  private val dispatcherC = ClosableDispatcher()
  val serverC =
    MockWebServer().apply {
      dispatcher = dispatcherC
    }

  @Test
  fun happyPath() {
    testInstances += this

    assertThat(serverA.started).isTrue()
    assertThat(serverB.started).isTrue()

    public final CharMatcher matcher;
    public final String matchingChars;

    SampleMatcherConfig(String matchingChars) {
      this(CharMatcher.anyOf(matchingChars), matchingChars);
    }

    SampleMatcherConfig(CharMatcher matcher, String matchingChars) {
      this.matcher = matcher;
      this.matchingChars = matchingChars;
    }
  }

  private BenchmarkHelpers() {}

 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0

 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0

    public final CharMatcher matcher;
    public final String matchingChars;

    SampleMatcherConfig(String matchingChars) {
      this(CharMatcher.anyOf(matchingChars), matchingChars);
    }

    SampleMatcherConfig(CharMatcher matcher, String matchingChars) {
      this.matcher = matcher;
      this.matchingChars = matchingChars;
    }
  }

  private BenchmarkHelpers() {}

 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0

 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0

 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0