RecordsWrite with no data should return a 204 status code.

[LiranCohen]

Currently when you write a RecordsWrite without any data, we assume that this is an initial write and the record will not be returned in a query.

When debugging issues, it could be difficult to discern between something that was accepted as a queryable write and something that was accepted as an initial state.

In discussing with @csuwildcat we decided a 204 - No Content response to writing a record with no data would be most suitable for signaling this.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/204