If you declare the return type, FastAPI will use it to **validate** the data, **document** it in OpenAPI, **filter** it, and **serialize** it using Pydantic.

/// tip

As Pydantic will serialize it in the **Rust** side, you will get much higher **performance** than if you don't declare a return type.

///

    }

    /**
     * Serialize the inbound Model instance to a StringWriter, perform the regex replacement to resolve
     * POM expressions, then re-parse into the resolved Model instance.
     * <p>
     * <b>NOTE:</b> This will result in a different instance of Model being returned!!!
     *
     * @param model The inbound Model instance, to serialize and reference for expression resolution

### JSON Performance { #json-performance }

    ListenableFuture<@Nullable Void> unused =
        serializer.submitAsync(() -> settableFuture, directExecutor());
    for (int i = 0; i < 25_000; i++) {
      serializer.submit(Callables.<Void>returning(null), directExecutor()).cancel(true);
      unused = serializer.submit(Callables.returning(null), directExecutor());
    }
    ListenableFuture<Integer> stackDepthCheck =

  TFE_Context* ctx = TFE_NewContext(opts, status);
  EXPECT_EQ(TF_GetCode(status), TF_OK) << TF_Message(status);
  TFE_DeleteContextOptions(opts);

  TFE_ContextSetServerDef(ctx, 0, serialized.data(), serialized.size(), status);
  EXPECT_EQ(TF_GetCode(status), TF_OK) << TF_Message(status);

  const char task0_name[] = "/job:localhost/replica:0/task:0/device:CPU:0";

        serializer.setProperty("http://xmlpull.org/v1/doc/properties.html#serializer-indentation", "  ");
        serializer.setProperty("http://xmlpull.org/v1/doc/properties.html#serializer-line-separator", "\n");
        serializer.setOutput(stream, coreExtensions.getModelEncoding());
        serializer.startDocument(coreExtensions.getModelEncoding(), null);
        writeCoreExtensions(coreExtensions, "extensions", serializer);
        serializer.endDocument();

                    not include that field, the JSON sent to the client would not have
                    that `password`.
                * Validation: whatever you return will be serialized with the
                    `response_model`, converting any data as necessary to generate the
                    corresponding JSON. But if the data in the object returned is not

  EXPECT_EQ(tensorflow::unwrap(var_handle0)->DeviceName(&status2), dev0_name);

  // Rename local device
  // This server def has the task index set to 0.
  string serialized = server_def.SerializeAsString();
  TFE_ContextSetServerDef(ctx, 0, serialized.data(), serialized.size(), status);
  EXPECT_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);

  const string dev1_name =

    ListenableFuture<@Nullable Void> unused =
        serializer.submitAsync(() -> settableFuture, directExecutor());
    for (int i = 0; i < 25_000; i++) {
      serializer.submit(Callables.<Void>returning(null), directExecutor()).cancel(true);
      unused = serializer.submit(Callables.returning(null), directExecutor());
    }
    ListenableFuture<Integer> stackDepthCheck =

			b = append(b, parts...)
		}
	}
	return b
}

// ChecksumFromBytes reconstructs a Checksum struct from the serialized bytes created in AppendTo()
// Returns nil if the bytes are invalid or empty.
// AppendTo() can append a serialized Checksum to another already-serialized Checksum,
// however, in practice, we only use one at a time.
// ChecksumFromBytes only returns the first one and no part checksums.