///

## Use Cases { #use-cases }

You could use this to stream data from an **AI LLM** service, from **logs** or **telemetry**, or from other types of data that can be structured in **JSON** items.

/// tip

If you want to stream binary data, for example video or audio, check the advanced guide: [Stream Data](../advanced/stream-data.md).

///

## Stream JSON Lines with FastAPI { #stream-json-lines-with-fastapi }

### Remotely Inspecting backend data

                                                                    data-docid="${f:u(doc.doc_id)}"
                                                                    data-title="${fe:replace(doc.content_title, '<[^>]+>', '')}"
                                                                    data-url="${f:h(doc.url_link)}">

        // Verify the decoded data matches
        assertEquals(translatedName.sid_type, decodedName.sid_type);
        // The decode process doesn't preserve the original length, it reads from the buffer
        assertNotNull(decodedName.name);
        assertNotNull(decodedName.name.buffer);
        // Buffer length is based on maximum_length/2 from the encoded data

     * Calculates a Message Integrity Code (MIC) for the given data.
     * @param data the data to calculate MIC for
     * @return MIC
     * @throws CIFSException if an error occurs calculating the MIC
     */
    byte[] calculateMIC(byte[] data) throws CIFSException;

    /**
     * Verifies a Message Integrity Code (MIC) for the given data.
     * @param data the data to verify
     * @param mic the MIC to verify against

   * for the data format.
   */
  static <K extends @Nullable Object, V extends @Nullable Object> void populateMap(
      Map<K, V> map, ObjectInputStream stream, int size)
      throws IOException, ClassNotFoundException {
    for (int i = 0; i < size; i++) {
      @SuppressWarnings("unchecked") // reading data stored by writeMap
      K key = (K) stream.readObject();

                System.arraycopy(name, 0, dst, offset, name.length);
                offset += name.length;
            }

            // Write data if present
            if (data != null && data.length > 0) {
                System.arraycopy(data, 0, dst, offset, data.length);
                offset += data.length;
            }

            // Pad to 8-byte boundary
            while ((offset - dstIndex) % 8 != 0) {

 *               operations. May be null for top-level requests.
 * @param data Additional data associated with this request trace, typically containing the actual request
 *             object being processed or any application-specific state information. May be null if no
 *             additional data is needed.
 */
public record RequestTrace(
        @Nullable String context,

///

## About "Form Fields" { #about-form-fields }

The way HTML forms (`<form></form>`) sends the data to the server normally uses a "special" encoding for that data, it's different from JSON.

**FastAPI** will make sure to read that data from the right place instead of JSON.

/// note | Technical Details

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

# Versions to use.
CODE=2025c
DATA=2025c

set -e

cd $(dirname $0)
rm -rf work
mkdir work
go build -o work/mkzip mkzip.go # build now for correct paths in build errors
cd work
mkdir zoneinfo
curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzcode$CODE.tar.gz
curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzdata$DATA.tar.gz
tar xzf tzcode$CODE.tar.gz