Ten en cuenta que los custom proprietary headers se pueden añadir [usando el prefijo `X-`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers).

Pero si tienes custom headers que deseas que un cliente en un navegador pueda ver, necesitas añadirlos a tus configuraciones de CORS ([CORS (Cross-Origin Resource Sharing)](cors.md)) usando el parámetro `expose_headers` documentado en [la documentación de CORS de Starlette](https://www.starlette.dev/middleware/#corsmiddleware).

## Versões disponíveis { #available-versions }

Você pode ver as versões disponíveis (por exemplo, para verificar qual é a mais recente) nas [Release Notes](../release-notes.md).

## Sobre versões { #about-versions }

  }

  /**
   * Returns an unmodifiable <b>view</b> of the union of two sets. The returned set contains all
   * elements that are contained in either backing set. Iterating over the returned set iterates
   * first over all the elements of {@code set1}, then over each element of {@code set2}, in order,
   * that is not contained in {@code set1}.
   *
   * <p>Results are undefined if {@code set1} and {@code set2} are sets based on different

@SuppressWarnings("serial") // No serialization is used in this test
@GwtCompatible
@NullMarked
public class PeekingIteratorTest extends TestCase {

  /**
   * Version of {@link IteratorTester} that compares an iterator over a given collection of elements
   * (used as the reference iterator) against a {@code PeekingIterator} that *wraps* such an
   * iterator (used as the target iterator).
   *

  We call this license the "Lesser" General Public License because it
does Less to protect the user's freedom than the ordinary General
Public License.  It also provides other free software developers Less
of an advantage over competing non-free programs.  These disadvantages
are the reason we use the ordinary General Public License for many
libraries.  However, the Lesser license provides advantages in certain
special circumstances.

 * {@link #computeNext} method, and invoke the {@link #endOfData} method when appropriate.
 *
 * <p>Another example is an iterator that skips over null elements in a backing iterator. This could
 * be implemented as:
 *
 * {@snippet :
 * public static Iterator<String> skipNulls(final Iterator<String> in) {
 *   return new AbstractIterator<String>() {

import jcifs.CloseableIterator;
import jcifs.ResourceNameFilter;
import jcifs.SmbResource;

/**
 * Base class for directory enumeration iterators.
 *
 * This abstract class provides common functionality for iterating
 * over directory entries in SMB file shares.
 *
 * @author mbechler
 */
public abstract class DirFileEntryEnumIteratorBase implements CloseableIterator<FileEntry> {

2. Write implementation following existing patterns
3. Add comprehensive tests
4. Run `mvn formatter:format license:format test`
5. Update JavaDoc for changed/new classes

**Principles:**
- Avoid over-engineering - keep solutions simple
- Only expose necessary public APIs
- Validate parameters with `Objects.requireNonNull()`
- Provide detailed error messages with context
- Add logging with contextual information

/**
 * A sorted set of contiguous values in a given {@link DiscreteDomain}. Example:
 *
 * {@snippet :
 * ContiguousSet.create(Range.closed(5, 42), DiscreteDomain.integers())
 * }
 *
 * <p>Note that because bounded ranges over {@code int} and {@code long} values are so common, this
 * particular example can be written as just:
 *
 * {@snippet :
 * ContiguousSet.closed(5, 42)
 * }
 *

      cp >>>= 4;
      dest[4] = upperHexDigits[0x8 | (cp & 0x3)];
      cp >>>= 2;
      dest[2] = upperHexDigits[cp & 0x7];
      return dest;
    } else {
      // If this ever happens it is due to bug in UnicodeEscaper, not bad input.
      throw new IllegalArgumentException("Invalid unicode character value " + cp);
    }
  }