Possible memory leak in withTaskGroup(of:) concurrency method (FB9719809)

[mikecsh (Mike)]

I am also seeing this behaviour with my application leaking gigabytes of memory on macOS with Xcode 13.2 Beta (13C5066c) since adopting withTaskGrou(of:). My experience seems very similar to the Linux issue here:

`withTaskGroup(of:)` leaks huge amounts of memory, but only on linux

i’ve been spending a couple of days debugging a memory leak in my application, which leaks over 300MB of memory per second. i was able to isolate the issue to a call to withTaskGroup(of:), which looks pretty much like this: private func peg<Client>( ... , using client:Client, as:Client.Type, whenever instructions: @Sendable () async -> (price:Decimal<Int64>, indicators:T)?) async -> [Fill<T>] where Client:Executor { let pollster:Task = .init…