Function emitAsyncSequence

packages/react-server/src/ReactFlightServer.js:2466–2534

(
  request: Request,
  task: Task,
  node: AsyncSequence,
  alreadyForwardedDebugInfo: ?ReactDebugInfo,
  owner: null | ReactComponentInfo,
  stack: null | Error,
)

}

function emitAsyncSequence(
  request: Request,
  task: Task,
  node: AsyncSequence,
  alreadyForwardedDebugInfo: ?ReactDebugInfo,
  owner: null | ReactComponentInfo,
  stack: null | Error,
): void {
  const visited: Set<AsyncSequence | ReactDebugInfo> = new Set();
  if (__DEV__ && alreadyForwardedDebugInfo) {
    visited.add(alreadyForwardedDebugInfo);
  }
  const awaitedNode = visitAsyncNode(request, task, node, visited, task.time);
  if (awaitedNode === undefined) {
    // Undefined is used as a signal that we found an aborted await and that's good enough
    // anything derived from that aborted node might be irrelevant.
  } else if (awaitedNode !== null) {
    // Nothing in user space (unfiltered stack) awaited this.
    serializeIONode(request, awaitedNode, awaitedNode.promise);
    request.pendingChunks++;
    // We log the environment at the time when we ping which may be later than what the
    // environment was when we actually started awaiting.
    const env = (0, request.environmentName)();
    // If we don't have any thing awaited, the time we started awaiting was internal
    // when we yielded after rendering. The current task time is basically that.
    const debugInfo: ReactAsyncInfo = {
      awaited: ((awaitedNode: any): ReactIOInfo), // This is deduped by this reference.
      env: env,
    };
    if (__DEV__) {
      if (owner === null && stack === null) {
        // We have no location for the await. We can use the JSX callsite of the parent
        // as the await if this was just passed as a prop.
        if (task.debugOwner !== null) {
          // $FlowFixMe[cannot-write]
          debugInfo.owner = task.debugOwner;
        }
        if (task.debugStack !== null) {
          // $FlowFixMe[cannot-write]
          debugInfo.stack = filterStackTrace(
            request,
            parseStackTrace(task.debugStack, 1),
          );
        }
      } else {
        if (owner != null) {
          // $FlowFixMe[cannot-write]
          debugInfo.owner = owner;
        }
        if (stack != null) {
          // $FlowFixMe[cannot-write]
          debugInfo.stack = filterStackTrace(
            request,
            parseStackTrace(stack, 1),
          );
        }
      }
    }