*
     * @param dst the destination byte array to write to
     * @param dstIndex the starting index in the destination array
     * @return the number of bytes written
     */
    public int writeWireFormat(final byte[] dst, final int dstIndex) {
        length = writeTrailerWireFormat(dst, dstIndex + HEADER_LENGTH);
        writeHeaderWireFormat(dst, dstIndex);

Es handelt sich um eine recht umfangreiche Spezifikation, und sie deckt mehrere komplexe Anwendungsfälle ab.

Sie umfasst Möglichkeiten zur Authentifizierung mithilfe eines „Dritten“ („third party“).

Das ist es, was alle diese „Login mit Facebook, Google, X (Twitter), GitHub“-Systeme unter der Haube verwenden.

### OAuth 1

And it normally is a complex and "difficult" topic.

In many frameworks and systems just handling security and authentication takes a big amount of effort and code (in many cases it can be 50% or more of all the code written).

**FastAPI** provides several tools to help you deal with **Security** easily, rapidly, in a standard way, without having to study and learn all the security specifications.

But first, let's check some small concepts.

        int bodyOffset = headerStart + Smb2Constants.SMB2_HEADER_LENGTH;

        // Encode the full message to set headerStart
        request.encode(buffer, headerStart);

        // Then - verify the body was written correctly
        byte[] pathBytes = TEST_PATH.getBytes(StandardCharsets.UTF_16LE);

        // Verify structure size (9)
        assertEquals(9, SMBUtil.readInt2(buffer, bodyOffset));

   *     Corresponds to `FLAG_FIN`.
   * @param flushHeaders true to force flush the response headers. This should be true unless the
   *     response body exists and will be written immediately.
   */
  @Throws(IOException::class)
  fun writeHeaders(
    responseHeaders: List<Header>,
    outFinished: Boolean,
    flushHeaders: Boolean,
  ) {
    assertLockNotHeld()

        return len;
    }

    /**
     * Writes the AndX wire format to buffer
     * @param dst the destination buffer
     * @param dstIndex the starting index
     * @return the number of bytes written
     */
    protected int writeAndXWireFormat(final byte[] dst, int dstIndex) {
        final int start = dstIndex;

        this.wordCount = writeParameterWordsWireFormat(dst, start + ANDX_OFFSET_OFFSET + 2);

     * another thread or the worker task has cleared the count and set the state.
     *
     * <p>When {@link #executor} is a directExecutor(), the value written to
     * {@code workerRunningState} will be available synchronously, and behaviour will be
     * deterministic.
     */
    @SuppressWarnings("GuardedBy")

///

/// tip

Notice that in this case we are using a standard Python `open()` function that interacts with a file.

So, it involves I/O (input/output), that requires "waiting" for things to be written to disk.

But `open()` doesn't use `async` and `await`.

So, we declare the event handler function with standard `def` instead of `async def`.

///

    }

    /**
     * Serializes an object using Kryo serialization.
     * <p>
     * Uses the thread-local Kryo instance to serialize the object along with
     * its class information. The serialized data is written to a byte array
     * output stream.
     * </p>
     *
     * @param obj the object to serialize
     * @return the serialized object as a byte array

        byte[] buffer = new byte[32];
        int bytesWritten = hmac.engineDigest(buffer, 5, 16);

        assertEquals(16, bytesWritten);
        // Check that bytes were written to the correct position
        byte[] extractedResult = Arrays.copyOfRange(buffer, 5, 21);
        assertEquals(16, extractedResult.length);
    }

    @Test
    void testEngineDigestWithInsufficientBuffer() {