`PostBuilder` does not allow a post to be a reply and a quote at the same time

<!-- Have you searched the existing issues to see if your bug is already reported? --> # Bug report ## Details ### Describe the bug `PostBuilder` does not allow a post to be a reply and a quote at the same time. ### Expected behavior As far as I'm aware, there is nothing in the specification that says a post cannot be a reply and a quote at the same time, so `PostBuilder` should allow this. ### Actual behavior Setting `QuotePost` or `InReplyTo` will cause the other property to be cleared. ## Helpful Extra information ### What operating system(s) are you using? - [ ] Windows - [x] macOS - [ ] Ubuntu - [x] Other Linux - [ ] Other (specify below) ### Reproduction code ``` PostBuilder postBuilder = new PostBuilder(); postBuilder.QuotePost = ...; postBuilder.InReplyTo = ...; // QuotePost is now null ``` If I hack the `Reply` property in `Post`, Bluesky accepts the post and it looks correct on the website: ``` PostBuilder postBuilder = new PostBuilder(); postBuilder.QuotePost = ...; Post post = postBuilder.ToPost(); PropertyInfo replyProperty = typeof(Post).GetProperty("Reply", BindingFlags.Public | BindingFlags.Instance)!; replyProperty.SetValue(post, ...); // send... ``` ### Bluesky API `app.bsky.feed.post` ### API Response Parsing Bugs N/A