// 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);

	var sub *subHandlerID
	if m.Payload == nil {
		m.Payload = GetByteBuffer()[:0]
	}
	h, err := m.UnmarshalMsg(b)
	if err != nil {
		return nil, nil, fmt.Errorf("read write: %v", err)
	}
	if len(m.Payload) == 0 && m.Flags&FlagPayloadIsZero == 0 {
		PutByteBuffer(m.Payload)
		m.Payload = nil
	}
	if m.Flags&FlagCRCxxh3 != 0 {
		const hashLen = 4

  /** 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) {

	errFatal(local.RegisterSingleHandler(handlerTest, func(payload []byte) ([]byte, *RemoteErr) {
		t.Log("1: server payload: ", len(payload), "bytes.")
		return append([]byte{}, payload...), nil
	}))
	// 2: Return as error
	errFatal(local.RegisterSingleHandler(handlerTest2, func(payload []byte) ([]byte, *RemoteErr) {
		t.Log("2: server payload: ", len(payload), "bytes.")
		err := RemoteErr(payload)
		return nil, &err
	}))

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)
```

    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")

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
     */

    /**
     * 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 {};

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

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