Before submitting the PR, please make sure you do the following

This will be necessary for the work on async SSR. Based on local benching it looks to be pretty much a wash perf-wise, withmain winning as often as it loses

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC:https://github.com/sveltejs/rfcs
• Prefix your PR title withfeat:,fix:,chore:, ordocs:.
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.
• If this PR changes code withinpackages/svelte/src, add a changeset (npx changeset).

Tests and linting

• Run the tests withpnpm test and lint the project withpnpm lint