Spec edits for multipart @defer @stream around content-length

rfcs/IncrementalDelivery.md

@@ -19,25 +19,20 @@ An example response body will look like:
 ```
 ---
 Content-Type: application/json; charset=utf-8
-Content-Length: 45
 
 {"data":{"hello":"Hello Rob"},"hasNext":true}
-
 ---
 Content-Type: application/json; charset=utf-8
-Content-Length: 57
 
 {"data":{"test":"Hello World"},"path":[],"hasNext":false}
-
 -----
 ```
 * The boundary used is `-` and is passed to the client in the http response's `Content-Type` header. Note that headers can appear in both the HTTP response itself and as part of the response body. The `Content-Type` header must be sent in the HTTP response.
-* Each part of the multipart response must start with `---` and a `CRLF`
+* An initial boundary is sent marking the end of the preamble area.
 * Each part of the multipart response must contain a `Content-Type` header. Similar to the GraphQL specification this specification does not require a specific serialization format. For consistency and ease of notation, examples of the response are given in JSON throughout the spec.
-* Each part of the multipart response must contain a `Content-Length` header. This should be the number of bytes of the payload of the response. It does not include the size of the headers, boundaries, or `CRLF`s used to separate the content.
 * After all headers, an additional `CRLF` is sent.
-* The payload is sent, followed by two `CRLF`s.
-* After the last part of the multipart response is sent, the terminating boundary `-----` is sent, followed by a `CRLF`
+* The payload is sent, followed by a `CRLF`.
+* After each payload, a boundary is sent. For the final payload, the terminating boundary of `-----` followed by a `CRLF` is sent. For all other payloads a boundary of `---` followed by a `CRFL` is sent.
 
 ## Server Implementations
 * `express-graphql`: [pull request](https://github.com/graphql/express-graphql/pull/583)