@CyrusNajmabadi A few more commits were needed after your review, starting with d18018d, but most significantly this one: b360f4e

@jasonmalinowski Might be interested in reviewing this PR.

I'm having a hard time seeing the value on this PR. The summary mentions two issues:

• Fixes #61935: This change is vastly more complicated than necessary to resolve this issue.
• Contributes to #57554: The value of this linked issue is debatable, as is a goal to move in that direction. There are open challenges to all points presented in that issue:
  • Executing the LSP server in a separate process introduces overhead that is trivially avoided by simply running the code in-process, so this might not ever happen.
  • Avoiding document realization in devenv is unnecessary if the LSP server is running in process.
  • Avoiding asynchronous operations related to the editor loop may be unnecessary, e.g. Async backfill for completion #61600

I'm concerned that the primary outcome of this change will be someone eventually comes back and manually reverts it (moves everything back to async forms).

@sharwell Forgot to mention in the description/linked issue (updated) that we also have telemetry from the editor team on UI delays occurring during execution of our command handlers. This change is potentially addressing those delays, or at least reducing them to a single cause - which would be that parsing of a source text is slow. GetTextSynchronously was designed to be utilized for these purposes. The issue at the moment is that features have access to Document and any async operation it provides, so it's easy for the implementations to not know that they are being called from a command handler and need to be synchronous. ParsedDocument constraints the implementation since it does not provide any async operations to fetch text/syntax tree.

Avoiding asynchronous operations related to the editor loop may be unnecessary

The async backfill for completion is a great idea and it is gonna be needed when we need to access semantic information. It is not needed for indentation, formatting or brace completion, which is what this PR is addressing.

Added comment on ParsedDocument to explain its purpose.