Function makeSlowStream

test/proxyStreaming.test.js:107–118

()

    cancelled = false;
    finished = false;
    function makeSlowStream() {
      // Web ReadableStream so .cancel() is callable; emits one chunk fast,
      // then waits "forever" — exactly the shape an SSE upstream takes on a
      // long Anthropic response. The cancel callback marks observable state
      // so the test can assert it fired.
      return new ReadableStream({
        start(controller) {
          controller.enqueue(new TextEncoder().encode('data: {"type":"message_start"}\n\n'));
        },
        cancel() { cancelled = true; },
      });
    }
    const routes = {
      'POST /test/slow': async () => {
        const stream = makeSlowStream();