You can declare a Pydantic model with `bytes` fields, and then use `val_json_bytes` in the model config to tell it to use base64 to *validate* input JSON data, as part of that validation it will decode the base64 string into bytes.

{* ../../docs_src/json_base64_bytes/tutorial001_py310.py ln[1:9,29:35] hl[9] *}

If you check the `/docs`, they will show that the field `data` expects base64 encoded bytes:

<div class="screenshot">

  static String format(String template, Object... args) {
    // start substituting the arguments into the '%s' placeholders
    StringBuilder builder = new StringBuilder(template.length() + 16 * args.length);
    int templateStart = 0;
    int i = 0;
    while (i < args.length) {
      int placeholderStart = template.indexOf("%s", templateStart);
      if (placeholderStart == -1) {
        break;
      }

			}
		}
		if err := w.Close(); err != nil {
			t.Fatalf("Unable to write archive: %s", err)
		}

		// TODO: We may want to check if the archive roundtrips. This would require
		// taking into account addition of the two zero trailer blocks that Writer.Close
		// appends.
	})

	# generate random nr of blocks
	COUNT=$((RANDOM % 100 + 100))
	# generate random content
	dd if=/dev/urandom bs=50K count="${COUNT}" of="${SRC_DIR}"/file"$idx"
done

# create small object that will be inlined into xl.meta
dd if=/dev/urandom bs=50K count=1 of="${INLINED_DIR}"/inlined

if ./mc cp --quiet --recursive "${SRC_DIR}/" "${ALIAS_NAME}"/"${BUCKET}"/initial-data/; then

   * multiple threads can concurrently load values for distinct keys.
   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values
   * into the cache. Newly loaded values are added to the cache using {@code
   * Cache.asMap().putIfAbsent} after loading has completed; if another value was associated with

	return mac.Sum(make([]byte, 0, mac.Size())), nil
}

// parseCiphertext parses and converts a ciphertext into
// the format expected by a secretKey.
//
// Previous implementations of the secretKey produced a structured
// ciphertext. parseCiphertext converts all previously generated
// formats into the expected format.
func parseCiphertext(b []byte) ([]byte, kms.SecretKeyType) {
	if len(b) == 0 {
		return b, kms.AES256

However, they are now deprecated as you will now get better performance by using a [Response Model - Return Type](https://fastapi.tiangolo.com/tutorial/response-model/).

That way, Pydantic will serialize the data into JSON bytes on the Rust side, which will achieve better performance than these custom JSON responses.

  public final T next() {
    if (!hasNext()) {
      throw new NoSuchElementException();
    }
    state = State.NOT_READY;
    // Safe because hasNext() ensures that tryToComputeNext() has put a T into `next`.
    T result = uncheckedCastNullableTToT(next);
    next = null;
    return result;
  }

  /**
   * Returns the next element in the iteration without advancing the iteration, according to the

}

// Unique reports whether the column may be unique.
func (ct ColumnType) Unique() (unique bool, ok bool) {
	return ct.UniqueValue.Bool, ct.UniqueValue.Valid
}

// ScanType returns a Go type suitable for scanning into using Rows.Scan.
func (ct ColumnType) ScanType() reflect.Type {
	if ct.ScanTypeValue != nil {
		return ct.ScanTypeValue
	}
	return ct.SQLColumnType.ScanType()
}

// Comment returns the comment of current column.

   */
  @CanIgnoreReturnValue
  public int writeBytesTo(byte[] dest, int offset, int maxLength) {
    maxLength = min(maxLength, bits() / 8);
    Preconditions.checkPositionIndexes(offset, offset + maxLength, dest.length);
    writeBytesToImpl(dest, offset, maxLength);
    return maxLength;
  }

  abstract void writeBytesToImpl(byte[] dest, int offset, int maxLength);

  /**