assertNotNull(annotation, "Annotation should be present on field");
        assertEquals("Payload length should be 2", 2, annotation.payload().length);
        assertEquals("First payload should be TestPayload", TestPayload.class, annotation.payload()[0]);
        assertEquals("Second payload should be AnotherTestPayload", AnotherTestPayload.class, annotation.payload()[1]);
    }

    // Test annotation on method
    @Test

        assertEquals("Should have 2 payloads", 2, multiAnnotation.payload().length);
        assertEquals("First payload should be TestPayload", TestPayload.class, multiAnnotation.payload()[0]);
        assertEquals("Second payload should be AnotherTestPayload", AnotherTestPayload.class, multiAnnotation.payload()[1]);
    }

    // Additional test interfaces for multiple groups/payloads test
    private interface AnotherTestGroup {

public interface Message {

    /**
     * Indicate that this message should retain it's raw payload
     */
    void retainPayload();

    /**
     * Determines whether to retain the message payload.
     *
     * @return whether to retain the message payload
     */
    boolean isRetainPayload();

    /**
     * Gets the raw payload of the message.
     *
     * @return the raw response message
     */

	b.Cleanup(grid.Cleanup)
	// Create n managers.
	for _, remote := range grid.Managers {
		// Register a single handler which echos the payload.
		errFatal(remote.RegisterSingleHandler(handlerTest, func(payload []byte) ([]byte, *RemoteErr) {
			defer PutByteBuffer(payload)
			return append(GetByteBuffer()[:0], payload...), nil
		}))
		errFatal(rpc.Register(remote, func(req *testRequest) (resp *testResponse, err *RemoteErr) {
			return &testResponse{

    void testReadSecurityBuffer() {
        byte[] buf = new byte[8 + 4];
        byte[] payload = { 0x11, 0x22, 0x33, 0x44 };
        NtlmMessage.writeSecurityBuffer(buf, 0, 8, payload);
        byte[] extracted = NtlmMessage.readSecurityBuffer(buf, 0);
        assertArrayEquals(payload, extracted, "Payload should match original");
    }

    @Test
    @DisplayName("readSecurityBuffer throws when array is too short")

        // Set a new payload and verify
        byte[] payload1 = "test_payload_1".getBytes();
        message.setRawPayload(payload1);
        assertArrayEquals(payload1, message.getRawPayload(), "getRawPayload should return the set payload");

        // Set another payload and verify
        byte[] payload2 = new byte[] { 1, 2, 3, 4, 5 };
        message.setRawPayload(payload2);

  /** Send a ping with the supplied [payload]. */
  @Throws(IOException::class)
  fun writePing(payload: ByteString) {
    writeControlFrame(OPCODE_CONTROL_PING, payload)
  }

  /** Send a pong with the supplied [payload]. */
  @Throws(IOException::class)
  fun writePong(payload: ByteString) {
    writeControlFrame(OPCODE_CONTROL_PONG, payload)
  }

  /**

  fun assertTextMessage(payload: String?) {
    assertThat(nextEvent()).isEqualTo(Message(string = payload))
  }

  fun assertBinaryMessage(payload: ByteString?) {
    assertThat(nextEvent()).isEqualTo(Message(payload))
  }

  fun assertPing(payload: ByteString) {
    assertThat(nextEvent()).isEqualTo(Ping(payload))
  }

  fun assertPong(payload: ByteString) {

    /**
     * The validation groups this constraint belongs to.
     * @return the groups
     */
    Class<?>[] groups() default {};

    /**
     * The payload associated with this constraint.
     * @return the payload
     */
    Class<? extends Payload>[] payload() default {};

    /**
     * Gets the configuration key for the minimum size constraint.
     * @return name of size the element must be higher or equal to
     */

The server handler function has this signature: `type SingleHandlerFn func(payload []byte) ([]byte, *RemoteErr)`.

Sample handler:
```go
    handler :=  func(payload []byte) ([]byte, *grid.RemoteErr) {
        // Do something with payload
        return []byte("response"), nil
    }

    err := manager.RegisterSingleHandler(grid.HandlerDiskInfo, handler)
```