fix a few remaining needless awaits

Author: ktoso

proposals/0304-structured-concurrency.md

@@ -282,7 +282,7 @@ func chopVegetables() async throws -> [Vegetable] {
     // Create a new child task for each vegetable that needs to be 
     // chopped.
     for v in rawVeggies {
-      await group.spawn { 
+      group.spawn { 
         return v.chopped()
       }
     }
@@ -1033,7 +1033,7 @@ func gather(first m: Int, of work: [Work]) async throws -> [WorkResult] {
 
   return withTaskGroup(resultType: WorkResult.self) { group in 
     for w in work { 
-      await group.spawn { await w.doIt() } // spawn child tasks to perform the work
+      group.spawn { await w.doIt() } // spawn child tasks to perform the work
     }  
 
     var results: [WorkResult] = []
@@ -1082,11 +1082,11 @@ func chopVegetables() async throws -> [Vegetable] {
   try await withThrowingTaskGroup(resultType: Vegetable.self) { group in
     print(group.isCancelled) // prints false
 
-    await group.spawn {
+    group.spawn {
       group.cancelAll() // Cancel all work in the group
       throw UnfortunateAccidentWithKnifeError()
     }
-    await group.spawn {
+    group.spawn {
       return try await chop(Onion())
     }
 
@@ -1096,7 +1096,7 @@ func chopVegetables() async throws -> [Vegetable] {
       }
     } catch {
       print(group.isCancelled) // prints true now
-      let added = await group.spawn {
+      let added = group.spawn {
         return try await chop(SweetPotato())
       }
       print(added) // prints false, no child was added to the cancelled group
@@ -1204,13 +1204,12 @@ func makeDinner() async throws -> Meal {
 
   // Create a task group to scope the lifetime of our three child tasks
   try await withTaskGroup(resultType: Void.self) { group in
-    await group.spawn {
-      veggies = try await chopVegetables()
-    }
-    await group.spawn {
+    group.spawn {
+      veggies = try await chgroup.spawn  }
+    group.spawn {
       meat = await marinateMeat()
     }
-    await group.spawn {
+    group.spawn {
       oven = await preheatOven(temperature: 350)
     }
   }
@@ -1257,4 +1256,4 @@ Initially the `group.spawn` was designed with the idea of being an asynchronous
 
 This was not implemented nor is it clear how efficient and meaningful this form of back-pressure really would be. A naive version of these semantics is possible to implement by balancing pending and completed task counts in the group by plain variables, so removing this implementation doe not prevent developers form implementing such "width limited" operations per se.
 
-The way to back-pressure submissions should also be considered in terms of how it relates to async let and general spawn mechanisms, not only groups. We have not figured out this completely, and rather than introduce an not-implemented API which may or may not have the right shape, for now we decided to punt on this feature until we know precisely if and how to apply this style of back-pressure on spawning tasks throughout the system.
+The way to back-pressure submissions should also be considered in terms of how it relates to async let and general spawn mechanisms, not only groups. We have not figured out this completely, and rather than introduce an not-implemented API which may or may not have the right shape, for now we decided to punt on this feature until we know precisely if and how to apply this style of back-pressure on spawning tasks throughout the system.