end = srcIndex + this.rDataLength;
        /*
         * Apparently readRDataWireFormat can return 0 if resultCode != 0 in
         * which case this will look indefinitely. Putting this else clause around
         * the loop might fix that. But I would need to see a capture to confirm.
         * if (resultCode != 0) {
         * srcIndex += rDataLength;
         * } else {
         */

        addrEntry = new NbtAddress[rDataLength / 6];
        end = srcIndex + rDataLength;
        /* Apparently readRDataWireFormat can return 0 if resultCode != 0 in
        which case this will look indefinitely. Putting this else clause around
        the loop might fix that. But I would need to see a capture to confirm.
        if (resultCode != 0) {
            srcIndex += rDataLength;
        } else {
        */

    /**
     * Default mode for combining children DOMs during merge.
     * When element names match, the process will try to merge the element data,
     * rather than putting the dominant and recessive elements as siblings.
     */
    public static final String DEFAULT_CHILDREN_COMBINATION_MODE = CHILDREN_COMBINATION_MERGE;

    /** Attribute name controlling how the element itself is combined */

    EntryComparator(@Nullable Comparator<? super K> keyComparator) {
      this.keyComparator = keyComparator;
    }

    @Override
    @SuppressWarnings("unchecked") // no less safe than putting it in the map!
    public int compare(Entry<K, V> a, Entry<K, V> b) {
      return (keyComparator == null)
          ? ((Comparable) a.getKey()).compareTo(b.getKey())
          : keyComparator.compare(a.getKey(), b.getKey());

You will see a lot more of all this in practice in the [Tutorial - User Guide](tutorial/index.md).

## Type Hints with Metadata Annotations { #type-hints-with-metadata-annotations }

Python also has a feature that allows putting **additional <dfn title="Data about the data, in this case, information about the type, e.g. a description.">metadata</dfn>** in these type hints using `Annotated`.

You can import `Annotated` from `typing`.

    @SuppressWarnings("SynchronizeOnNonFinalField")
    public T get() {
      // Another variant of Double Checked Locking.
      //
      // We use two volatile reads. We could reduce this to one by
      // putting our fields into a holder class, but (at least on x86)
      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;

    /**
     * This default mode for combining children DOMs during merge means that where element names match, the process will
     * try to merge the element data, rather than putting the dominant and recessive elements (which share the same
     * element name) as siblings in the resulting DOM.
     */
    @Deprecated(since = "4.0.0", forRemoval = true)

    @SuppressWarnings("SynchronizeOnNonFinalField")
    public T get() {
      // Another variant of Double Checked Locking.
      //
      // We use two volatile reads. We could reduce this to one by
      // putting our fields into a holder class, but (at least on x86)
      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;

Previous versions of FastAPI (before <dfn title="before 2023-03">0.95.0</dfn>) required you to use `Query` as the default value of your parameter, instead of putting it in `Annotated`, there's a high chance that you will see code using it around, so I'll explain it to you.

/// tip

  // If the `next` bits in `entries[i]` are 0 that means there are no further entries for the given
  // short hash. But 0 is also a valid index in `entries`, so we add 1 to these indices before
  // putting them in `table` or in `next` bits, and subtract 1 again when we need an index value.
  //
  // The elements of `keys`, `values`, and `entries` are added sequentially, so that elements 0 to