Function renderSuspenseBoundary

packages/react-server/src/ReactFizzServer.js:1272–1619

(
  request: Request,
  someTask: Task,
  keyPath: KeyNode,
  props: SuspenseProps,
)

}

function renderSuspenseBoundary(
  request: Request,
  someTask: Task,
  keyPath: KeyNode,
  props: SuspenseProps,
): void {
  if (someTask.replay !== null) {
    // If we're replaying through this pass, it means we're replaying through
    // an already completed Suspense boundary. It's too late to do anything about it
    // so we can just render through it.
    const prevKeyPath = someTask.keyPath;
    const prevContext = someTask.formatContext;
    const prevRow = someTask.row;
    someTask.keyPath = keyPath;
    someTask.formatContext = getSuspenseContentFormatContext(
      request.resumableState,
      prevContext,
    );
    someTask.row = null;
    const content: ReactNodeList = props.children;
    try {
      renderNode(request, someTask, content, -1);
    } finally {
      someTask.keyPath = prevKeyPath;
      someTask.formatContext = prevContext;
      someTask.row = prevRow;
    }
    return;
  }
  // $FlowFixMe: Refined.
  const task: RenderTask = someTask;

  const prevKeyPath = task.keyPath;
  const prevContext = task.formatContext;
  const prevRow = task.row;
  const parentBoundary = task.blockedBoundary;
  const parentPreamble = task.blockedPreamble;
  const parentHoistableState = task.hoistableState;
  const parentSegment = task.blockedSegment;

  // Each time we enter a suspense boundary, we split out into a new segment for
  // the fallback so that we can later replace that segment with the content.
  // This also lets us split out the main content even if it doesn't suspend,
  // in case it ends up generating a large subtree of content.
  const fallback: ReactNodeList = props.fallback;
  const content: ReactNodeList = props.children;

  const fallbackAbortSet: Set<Task> = new Set();
  let newBoundary: SuspenseBoundary;
  if (canHavePreamble(task.formatContext)) {
    newBoundary = createSuspenseBoundary(
      request,
      task.row,
      fallbackAbortSet,
      createPreambleState(),
      createPreambleState(),
    );
  } else {