RxJS-POST多部分文件

我正在做一篇关于多部分文件的文章。当文件较小时（2个50kb的文件）。一切正常。 如果文件较大（10个500kb的文件），则无法正常工作。
我认为原因是帖子需要一段时间才能返回结果

首先，我通过调用POST的merge来合并两个ob。 其次，我通过ConmbineLastUploadDocumentsSaved和behaviorSubject操作uploadDocumentGetDetailsAction获得uploadDocumentDetails$

由于调用fast uploadDocumentGetDetailsAction，POST尚未完成

在POST首先完成后，我应该如何实现obs以获得GET

  uploadDocumentsSaved$ = merge(
    this.uploadedDocuments$,
    this.saveAction$
      .pipe(
        concatMap(uploadDocument => {
          return  this.saveUploadDocuments(uploadDocument);
        })
      ))
      .pipe(
        scan((uploadDocuments: UploadDocument[], uploadDocument: UploadDocument) =>
          this.syncUploadDocuments(uploadDocuments, uploadDocument)
        ),
        shareReplay(1)
    );

  uploadDocumentDetails$ = combineLatest([
    this.uploadDocumentsSaved$,
    this.uploadDocumentGetDetailsAction$
  ]).pipe(
    map(([uploadedDocuments, selectedUploadedDocument]) =>
      uploadedDocuments.find(uploadedDocument => uploadedDocument.type = selectedUploadedDocument)
    ),
    switchMap(uploadDocument => this.uploadDocumentDetailsUrl(uploadDocument.token, uploadDocument.type)),
    shareReplay(1),
  );

---

我不确定我是否完全理解所显示的代码的作用，但我希望这样做：

  uploadDocumentsSaved$ = merge(
    this.uploadedDocuments$,
    this.saveAction$
      .pipe(
        concatMap(uploadDocument => this.saveUploadDocuments(uploadDocument)),
        concatMap(uploadDocument => this.uploadDocumentDetailsUrl(uploadDocument.token, uploadDocument.type))
      ))
      .pipe(
        scan((uploadDocuments: UploadDocument[], uploadDocument: UploadDocument) =>
          this.syncUploadDocuments(uploadDocuments, uploadDocument)
        ),
        shareReplay(1)
    );

每次saveAction发生时，它都会首先调用

saveUploadDocuments

（我假设这是post）然后调用

uploadDocumentDetailsUrl