* null, the other collection is returned. Otherwise, the elements of {@code other} are added to
   * {@code exceptions} and {@code exceptions} is returned.
   */
  @CheckForNull
  private static Collection<IOException> concat(
      @CheckForNull Collection<IOException> exceptions,
      @CheckForNull Collection<IOException> other) {
    if (exceptions == null) {

   * null, the other collection is returned. Otherwise, the elements of {@code other} are added to
   * {@code exceptions} and {@code exceptions} is returned.
   */
  @CheckForNull
  private static Collection<IOException> concat(
      @CheckForNull Collection<IOException> exceptions,
      @CheckForNull Collection<IOException> other) {
    if (exceptions == null) {

    suite.addTestSuite(MutableTypeToInstanceMapTest.class);

    suite.addTest(
        MapTestSuiteBuilder.using(
                new TestTypeToInstanceMapGenerator() {
                  // Other tests will verify what real, warning-free usage looks like
                  // but here we have to do some serious fudging
                  @Override
                  @SuppressWarnings({"unchecked", "rawtypes"})

   * identical in function to {@code toArray()}."
   *
   * <p>For maximum effect, the collection under test should be created from an element array of a
   * type other than {@code Object[]}.
   */
  public void testToArray_isPlainObjectArray() {
    Object[] array = collection.toArray();
    assertEquals(Object[].class, array.getClass());
  }

  public void testToArray_emptyArray() {

# wheels, we install them in a virtual environment and run some smoke tests on
# it. TFCI Mac VMs only have one Python version installed so we need to install
# the other versions manually.
if [[ "${TFCI_MACOS_PYENV_INSTALL_ENABLE}" == 1 ]]; then
  # Install the necessary Python, unless it's already present
  pyenv install -s "$TFCI_PYTHON_VERSION"
  pyenv local "$TFCI_PYTHON_VERSION"

/**
 * Static methods pertaining to ASCII characters (those in the range of values {@code 0x00} through
 * {@code 0x7F}), and to strings containing such characters.
 *
 * <p>ASCII utilities also exist in other classes of this package:
 *
 * <ul>
 *   <!-- TODO(kevinb): how can we make this not produce a warning when building gwt javadoc? -->
 *   <li>{@link StandardCharsets#US_ASCII} specifies the {@code Charset} of ASCII characters.

        xcs(XDS Client)
        ccs(CRD Client)
        fcs(Filesystem Client)
        acs(Aggregate)
        xcs-->acs
        ccs-->acs
        fcs-->acs
    end
```

#### ServiceDiscovery

 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;

       * to test it.
       */
      return;
    }

    /*
     * Only under Windows (or hypothetically when running with some other non-POSIX, ACL-based
     * filesystem) does our prod code look up the username. Thus, this test doesn't necessarily test
     * anything interesting under most environments. Still, we can run it (except for Android, at

[providers]
  [providers.file]
    filename = "routes.toml"
```

This tells Traefik to listen on port 9999 and to use another file `routes.toml`.

/// tip

We are using port 9999 instead of the standard HTTP port 80 so that you don't have to run it with admin (`sudo`) privileges.

///

Now create that other file `routes.toml`:

```TOML hl_lines="5  12  20"
[http]
  [http.middlewares]