How to create a synced block

[taco-indenbosch]

Does anyone know how to successfully create an (initial) synced block?

I have tried the following:

  string pageId="...";
  IList<ISyncedBlockChildrenRequest> blocks=...
  var content = new SyncedBlockBlockRequest()
  {
    SyncedBlock = new()
    {
      Children = blocks,
      SyncedFrom = null
    }
  };

  var result=await notionClient.Blocks.AppendChildrenAsync(new BlockAppendChildrenRequest(){BlockId = pageId, Children = [content] });

The SyncedFrom=null should not be necessary as it is the default value.

This fails with the following exception:

Notion.Client.NotionApiException: body failed validation: body.children[0].synced_block.synced_from should be defined, instead was undefined.

I guess the problem is that the null value for SyncedFrom is serialized as a missing property when sent to the Notion API, thereby being undefined rather than a Javascript null, but I don't know how to send an actual null. Or is there something else I am doing wrong?