Streaming rendering #46352
Description
As part of returning responses from the server, we want to support streaming them to the client, so that we can deliver updates while the app is still running.
Rendering certain pages may require long running operations, like fetching data from a database or making an API call. Streaming rendering allows the majority of the page to be rendered to the response with placeholders while long asynchronous operations on the server are still in progress. When the long running operations complete, the additional rendered updates can be streamed over the response and patched into the DOM. This enables faster initial load times.
Note that streamed updates may cause content on the page to shift, which needs to be accounted for in the UI design. For this reason, streaming rendering must be optionally enabled.