}
	testValidHeader(&h, t)
}

// Issue 4393. It is valid to have an extra data header
// which contains no body.
func TestZeroLengthHeader(t *testing.T) {
	h := FileHeader{
		Name:   "extadata.txt",
		Method: Deflate,
		Extra: []byte{

    void setValue(S segment, E entry, V value);
  }

  /**
   * An entry in a hash table of a {@link Segment}.
   *
   * <p>Entries in the map can be in the following states:
   *
   * <p>Valid: - Live: valid key/value are set
   *
   * <p>Invalid: - Collected: key/value was partially collected, but not yet cleaned up
   */
  interface InternalEntry<K, V, E extends InternalEntry<K, V, E>> {

                }).filter(o -> o != null).toArray(n -> new RequestParameter[n]));
                if (parameters.length == 0) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("No valid parameters found in request. Nothing to store.");
                    }
                    return;
                }
                try {
                    final String encoded = serializeParameters(parameters);

```

Tham số `name` **vẫn được yêu cầu** (không phải là *tùy chọn*) vì nó không có giá trị mặc định. Trong khi đó, `name` chấp nhận `None` như là giá trị:

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

Tin tốt là, khi bạn sử dụng Python 3.10, bạn sẽ không phải lo lắng về điều đó, bạn sẽ có thể sử dụng `|` để định nghĩa hợp của các kiểu dữ liệu một cách đơn giản:

| Dashboard                                                                                   | Creating a bucket                                                                           |

   * {@code '-'} (<code>'&#92;u002D'</code>) is recognized as the minus sign.
   *
   * <p>Unlike {@link Float#parseFloat(String)}, this method returns {@code null} instead of
   * throwing an exception if parsing fails. Valid inputs are exactly those accepted by {@link
   * Float#valueOf(String)}, except that leading and trailing whitespace is not permitted.
   *

        log.info("Network partition recovered - resuming normal witness operations");
        
        // Restore normal operation parameters
        // Verify all registrations are still valid
    }
}
```

## 9. Performance and Optimization

### 9.1 Witness Event Batching
```java
public class WitnessEventBatcher {

			selected = entry
			continue
		}

		// Get new entry metadata,
		// shallow decode.
		xl, err := entry.xlmeta()
		if err != nil {
			continue
		}
		objsValid++

		// Add all valid to candidates.
		r.candidates = append(r.candidates, xl.versions)

		// We select the first object we find as a candidate and see if all match that.
		// This is to quickly identify if all agree.
		if selected == nil {

Another big feature needed by APIs is data validation, making sure that the data is valid, given certain parameters. For example, that some field is an `int`, and not some random string. This is especially useful for incoming data.

Without a data validation system, you would have to do all the checks by hand, in code.

      WrappedIterator(Iterator<V> delegateIterator) {
        this.delegateIterator = delegateIterator;
      }

      /**
       * If the delegate changed since the iterator was created, the iterator is no longer valid.
       */
      void validateIterator() {
        refreshIfEmpty();
        if (delegate != originalDelegate) {
          throw new ConcurrentModificationException();
        }
      }