public Collection<ChannelInfo> getHealthyChannels() {
        return channels.values()
                .stream()
                .filter(ChannelInfo::isHealthy)
                .collect(ArrayList::new, (list, item) -> list.add(item), (list1, list2) -> list1.addAll(list2));
    }

    /**
     * Select a channel for the given message
     *
     * @param message message to send
     * @return selected channel
     */

@app.get("/stream-raw", response_class=StreamingResponse)
async def stream_raw() -> AsyncIterable[str]:
    """Async generator with no internal await - would hang without checkpoint."""
    i = 0
    while True:
        yield f"item {i}\n"
        i += 1


@app.get("/stream-jsonl")
async def stream_jsonl() -> AsyncIterable[int]:
    """JSONL async generator with no internal await."""
    i = 0
    while True:
        yield i

        urlQueue.setMethod("GET");
        urlQueue.setSessionId(sessionId);
        urlQueue.setUrl("http://www.example.com/page1");

        urlQueueService.insert(urlQueue);

        // Poll should return the item
        final OpenSearchUrlQueue polled = urlQueueService.poll(sessionId);
        assertNotNull(polled);
        assertEquals("http://www.example.com/page1", polled.getUrl());

                            {"OAuth2AuthorizationCodeBearer": ["read"]},
                        ],
                    },
                    "post": {
                        "summary": "Create Item",
                        "operationId": "create_item_items__post",
                        "responses": {
                            "200": {
                                "description": "Successful Response",

///

### `yield from` { #yield-from }

When you are iterating over something, like a file-like object, and then you are doing `yield` for each item, you could also use `yield from` to yield each item directly and skip the `for` loop.

This is not particular to FastAPI, it's just Python, but it's a nice trick to know. 😎

	for len(r.current) <= r.recordsRead {
		if r.err != nil {
			return nil, r.err
		}
		// Move to next block
		item, ok := <-r.queue
		if !ok {
			r.err = io.EOF
			return nil, r.err
		}

		r.csvDstPool.Put(r.current)
		r.current = <-item.dst
		r.err = item.err
		r.recordsRead = 0
	}
	csvRecord := r.current[r.recordsRead]
	r.recordsRead++

	// If no column names are set, use _(index)

{* ../../docs_src/generate_clients/tutorial001_py310.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:

        assertEquals(expected.length, actual.size(), "Collection size mismatch");
        for (T item : expected) {
            assertTrue(actual.contains(item), "Collection should contain: " + item);
        }
    }

    @Test
    void testPerformProfileActivation() throws ParseException {
        final CommandLineParser parser = new DefaultParser();

从 `fastapi.sse` 导入 `EventSourceResponse`：

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[1:25] hl[4,22] *}

每个被 yield 的项会被编码为 JSON，并放入 SSE 事件的 `data:` 字段发送。

如果你将返回类型声明为 `AsyncIterable[Item]`，FastAPI 将使用它通过 Pydantic对数据进行**校验**、**文档化**和**序列化**。

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[1:25] hl[10:12,23] *}

/// tip | 提示

由于 Pydantic 会在**Rust** 端序列化它，相比未声明返回类型，你将获得更高的**性能**。

///

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