有了 `Annotated` 之后，我们就可以放入更多信息（本例中是额外的校验）。在 `Annotated` 中添加 `Query`，并把参数 `max_length` 设为 `50`：

{* ../../docs_src/query_params_str_validations/tutorial002_an_py310.py hl[9] *}

注意默认值依然是 `None`，所以该参数仍是可选的。

但现在把 `Query(max_length=50)` 放到 `Annotated` 里，我们就在告诉 FastAPI，这个值需要**额外校验**，最大长度为 50 个字符。😎

/// tip | 提示

            // Write to buffer
            byte[] buffer = new byte[512];
            int bytesWritten = lockRequest.writeBytesWireFormat(buffer, 50);
            assertEquals(24 + (24 * 2), bytesWritten);

            // Verify written structure
            assertEquals(48, SMBUtil.readInt2(buffer, 50)); // Structure size
            assertEquals(2, SMBUtil.readInt2(buffer, 52)); // Lock count

        String oldFileName = "old.txt";
        String newFileName = "new.txt";
        byte[] dst = new byte[200];
        smbComRename = new SmbComRename(config, oldFileName, newFileName);
        int dstIndex = 50; // Start at offset 50

        // When
        int result = smbComRename.writeBytesWireFormat(dst, dstIndex);

        // Then
        assertTrue(result > 0);

        buffer[0] = 4; // wordCount
        buffer[1] = (byte) 0x42; // andxCommand
        SMBUtil.writeInt2(50, buffer, 3); // andxOffset
        SMBUtil.writeInt2(20, buffer, 9); // byteCount

        // Setup andx command data at offset 50 (absolute position)
        buffer[50] = 4; // andx wordCount
        SMBUtil.writeInt2(20, buffer, 59); // andx byteCount

            validator.validateBuffer(null, 100, 1024);
        });
    }

    @Test
    public void testBufferTooSmall() throws Exception {
        byte[] buffer = new byte[50];
        assertThrows(SmbException.class, () -> {
            validator.validateBuffer(buffer, 100, 1024);
        });
    }

    @Test
    public void testBufferTooLarge() throws Exception {

 * Unit test for {@link FakeTimeLimiter}.
 *
 * @author Jens Nyman
 */
@NullUnmarked
@GwtIncompatible
@J2ktIncompatible
public class FakeTimeLimiterTest extends TestCase {

  private static final int DELAY_MS = 50;
  private static final String RETURN_VALUE = "abc";

  private TimeLimiter timeLimiter;

  @Override
  protected void setUp() throws Exception {
    super.setUp();
    timeLimiter = new FakeTimeLimiter();
  }

        @DisplayName("Should handle high concurrency without deadlock")
        void testHighConcurrencyNoDeadlock() throws InterruptedException {
            int threadCount = 100;
            int operationsPerThread = 50;
            ExecutorService executor = Executors.newFixedThreadPool(threadCount);
            CountDownLatch startLatch = new CountDownLatch(1);
            CountDownLatch endLatch = new CountDownLatch(threadCount);

        mockTransport.sessionKey = 0x12345678;
        mockTransport.capabilities = SmbConstants.CAP_UNICODE | SmbConstants.CAP_NT_SMBS;
        mockTransport.snd_buf_size = 16644;
        mockTransport.maxMpxCount = 50;

        // Configure mock session
        mockSession.transport = mockTransport;

        // Configure authentication - set fields directly since NtlmPasswordAuthentication is final
        mockAuth.username = "testuser";

    @Test
    @DisplayName("Should write correct bytes to wire format")
    void testWriteBytesWireFormat() throws Exception {
        // Given
        byte[] buffer = new byte[512];
        int headerStart = 50;
        int bodyOffset = headerStart + Smb2Constants.SMB2_HEADER_LENGTH;

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

        // Test persistent handle (never expires)
        HandleInfo persistentInfo = new HandleInfo("/test/file2.txt", new HandleGuid(), testFileId, HandleType.PERSISTENT, 0, null);

        try {
            Thread.sleep(50);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }

        assertFalse(persistentInfo.isExpired());
    }

    @Test
    public void testUpdateAccessTime() {