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]);
    }

    // Test ProtocolType enum values

        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 {

            response.setDigest(null);

            response.haveResponse(buffer, 1, 3);

            byte[] payload = response.getRawPayload();
            assertNotNull(payload);
            assertEquals(3, payload.length);
            assertArrayEquals(new byte[] { 2, 3, 4 }, payload);
            assertTrue(response.isReceived());
            assertFalse(response.isAsyncHandled());
        }

        @Test

  interface FrameCallback {
    @Throws(IOException::class)
    fun onReadMessage(text: String)

    @Throws(IOException::class)
    fun onReadMessage(bytes: ByteString)

    fun onReadPing(payload: ByteString)

    fun onReadPong(payload: ByteString)

    fun onReadClose(
      code: Int,
      reason: String,
    )
  }

  /**
   * Process the next protocol frame.
   *

            assertTrue(w.isReady(), "WriterThread should be ready to accept work");

            // Act: submit a write
            w.write(payload, 3, out);
        }

        // Assert: verify the underlying stream was called
        verify(out, timeout(1000)).write(payload, 0, 3);

        // Stop the thread by sending n = -1
        synchronized (w) {
            w.write(new byte[0], -1, out);
        }

	if errCode != ErrNone {
		return cred, "", "", time.Time{}, errCode
	}

	// Payload streaming.
	payload := streamingContentSHA256
	if trailers {
		payload = streamingContentSHA256Trailer
	}

	// Payload for STREAMING signature should be 'STREAMING-AWS4-HMAC-SHA256-PAYLOAD'
	if payload != req.Header.Get(xhttp.AmzContentSha256) {
		return cred, "", "", time.Time{}, ErrContentSHA256Mismatch
	}

Let's start with a simple FastAPI application:

{* ../../docs_src/generate_clients/tutorial001_py39.py hl[7:9,12:13,16:17,21] *}

Notice that the *path operations* define the models they use for request payload and response payload, using the models `Item` and `ResponseMessage`.

### API Docs { #api-docs }

If you go to `/docs`, you will see that it has the **schemas** for the data to be sent in requests and received in responses:

    private @interface ValidCronRequired {
        String message() default "Must be a valid non-blank cron expression";

        Class<?>[] groups() default {};

        Class<? extends jakarta.validation.Payload>[] payload() default {};
    }

    private static class ComposedBean {
        @ValidCronRequired
        private String composedCron;

        public String getComposedCron() {

        void testVerifyFailedState() {
            assertFalse(testBlock.isVerifyFailed());
        }

        @Test
        @DisplayName("Test raw payload handling")
        void testRawPayloadHandling() {
            byte[] payload = new byte[] { 1, 2, 3, 4, 5 };

            assertNull(testBlock.getRawPayload());
            assertFalse(testBlock.isRetainPayload());

                // Implementation for raw payload
            }

            @Override
            public byte[] getRawPayload() {
                // Implementation for getting raw payload
                return null;
            }

            @Override
            public boolean isRetainPayload() {
                // Implementation for retain payload flag
                return false;
            }