swift

f64dd5a8 - [concurrency] Add initial support for SwiftSettings to control defaultIsolation at the file level.

[concurrency] Add initial support for SwiftSettings to control defaultIsolation at the file level. We introduce a new macro called #SwiftSettings that can be used in conjunction with a new stdlib type called SwiftSetting to control the default isolation at the file level. It overrides the current default isolation whether it is the current nonisolated state or main actor (when -enable-experimental-feature UnspecifiedMeansMainActorIsolated is set).