* the source will contain the concatenated data from the streams of the underlying sources.
   *
   * <p>Only one underlying stream will be open at a time. Closing the concatenated stream will
   * close the open underlying stream.
   *
   * @param sources the sources to concatenate
   * @return a {@code CharSource} containing the concatenated data
   * @since 15.0

// Package lock - implements filesystem locking wrappers around an
// open file descriptor.
package lock

import (
	"errors"
	"os"
	"sync"
)

// ErrAlreadyLocked is returned if the underlying fd is already locked.
var ErrAlreadyLocked = errors.New("file already locked")

// RLockedFile represents a read locked file, implements a special
// closer which only closes the associated *os.File when the ref count.

    private static final long serialVersionUID = 1L;

    /**
     * Creates a new DataStoreException with the specified message and cause.
     *
     * @param message the error message
     * @param cause the underlying cause of this exception
     */
    public DataStoreException(final String message, final Throwable cause) {
        super(message, cause);
    }

    /**

   *
   * <p>You may also consider the equivalent {@code
   * MultimapBuilder.hashKeys().arrayListValues().build()}, which provides more control over the
   * underlying data structure.
   */
  public static <K extends @Nullable Object, V extends @Nullable Object>
      ArrayListMultimap<K, V> create() {
    return new ArrayListMultimap<>();
  }

  /**

    /**
     * Creates a {@link SAXRuntimeException}.
     *
     * @param cause the underlying exception
     */
    public SAXRuntimeException(final SAXException cause) {
        super("ECL0054", asArray(createMessage(cause)), cause);
    }

    /**
     * Creates a message.
     *
     * @param cause the underlying exception
     * @return the message
     */

 * ArrayBasedCharEscaper} or {@link ArrayBasedUnicodeEscaper} instances. This class should be used
 * when more than one escaper is created using the same character replacement mapping to allow the
 * underlying (implementation specific) data structures to be shared.
 *
 * <p>The size of the data structure used by ArrayBasedCharEscaper and ArrayBasedUnicodeEscaper is

    /**
     * The underlying CrawlerClientFactory instance to which operations are delegated.
     */
    private final CrawlerClientFactory factory;

    private final Map<String, Object> params = new HashMap<>();

    /**
     * Constructs a CrawlerClientFactoryWrapper with the specified factory.
     *
     * @param factory the underlying CrawlerClientFactory instance to delegate operations to
     */

    /**
     * Creates a new MimeTypeException with the specified detail message and cause.
     *
     * @param message the detail message explaining the reason for the exception
     * @param cause the underlying cause of the exception
     */
    public MimeTypeException(final String message, final Throwable cause) {
        super(message, cause);
    }

    /**

   * }
   *
   * ... prints {@code {a=[4, 16], b=[9, 9], c=[36]}}.
   *
   * <p>Changes in the underlying multimap are reflected in this view. Conversely, this view
   * supports removal operations, and these are reflected in the underlying multimap.
   *
   * <p>It's acceptable for the underlying multimap to contain null keys, and even null values

        // Assert: verify one invocation and no more
        verify(handle, times(1)).release();
        verifyNoMoreInteractions(handle);
    }

    @Test
    @DisplayName("ensureDFSResolved(): no exception when underlying call succeeds")
    void ensureDFSResolved_success() throws Exception {
        // Arrange: default mock does nothing

        // Act: call method under test
        handle.ensureDFSResolved();