Firebase Storage Global queue usage leads to thread explosion/threading issues

### Description

It seems that starting with version 10.0 and above, hitting the FirebaseStorage `getData` method, creates a thread explosion due to using the global queues and background as quality of service.

Here's the relevant portion:
![Screenshot 2022-11-13 at 22 14 20](https://user-images.githubusercontent.com/82413230/201641944-684eccef-b9c7-41a3-9363-fc0bbe77cb6e.png)


Additionally if you call the `getData` method multiple times from a thread that's not the Main thread, causes the lock on `GTMSessionFetcher` to never release, trapping all further calls, which somehow also leads to the network service of the device to die.

Screenshot showing all the aforementioned threads stuck on `GTMSessionFetcher`'s  `startSessionUsage` 's `@synchronized`
![Screenshot 2022-11-11 at 11 45 54](https://user-images.githubusercontent.com/82413230/201642481-277f13c5-157a-4c35-9d89-1ce0c5a9994b.png)

![Screenshot 2022-11-11 at 11 44 58](https://user-images.githubusercontent.com/82413230/201642661-1967d9f8-946d-4232-8acc-81485d9b2b7f.png)

It's very easy to reproduce if you use the async/await continuation APIs to wrap the `getData` method.


All of this behaves properly in Firebase 9.6.0

Ideally the SDK shouldn't use global queues, due to them leading to thread explosions, allocating a couple of queues for Firebase would be a better experience.
Also the SDK shouldn't use `.background` as the QoS parameter as that can lead to dependency inversion issues.

Here's  Pierre Habouzit, a former GCD maintainer with his thoughts on the matter:
https://twitter.com/pedantcoder/status/773903697474486273

A Swift evolution thread discussion on the matter:
https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170828/039368.html

Some more resources on GCD, global queues and priorities:
https://gist.github.com/tclementdev/6af616354912b0347cdf6db159c37057





### Reproducing the issue

```
class CloudStorageService {
    private lazy var storage = Storage.storage()

    private func getStorageData(reference: StorageReference) async throws -> Data {
        try await withCheckedThrowingContinuation { [weak self] continuation in
            reference.getData(maxSize: 1024 * 1024) { data, error in
                guard let self else {
                    continuation.resume(throwing: CloudStorageError.invalidResponse)
                    return
                }

                if let error {
                    continuation.resume(throwing: error)
                } else if let data {
                    continuation.resume(returning: data)
                }
            }
        }
    }

    func getStorageString(url: String) async throws -> String {
        let stringData = try await getStorageData(reference: storage.reference(forURL: url))
        guard let string = String(data: stringData, encoding: .utf8) else {
            throw CloudStorageError.invalidResponse
        }

        return string
    }
}
```

Calling

```
 let cloudStorageService = CloudStorageService()
 let storageString = try? await cloudStorageService.getStorageString(url: "Resource-ID") 
```

```
 let cloudStorageService2 = CloudStorageService()
 let storageString = try? await cloudStorageService2.getStorageString(url: "Resource-ID") 
```

```
 let cloudStorageService3 = CloudStorageService()
 let storageString = try? await cloudStorageService3.getStorageString(url: "Resource-ID") 
```

```
 let cloudStorageService4 = CloudStorageService()
 let storageString = try? await cloudStorageService4.getStorageString(url: "Resource-ID") 
```

Reproduces the issue.

### Firebase SDK Version

10.1.0

### Xcode Version

14.1.0

### Installation Method

Swift Package Manager

### Firebase Product(s)

Storage

### Targeted Platforms

iOS

### Relevant Log Output

_No response_

### If using Swift Package Manager, the project's Package.resolved



<details>
<summary>Expand <code>Package.resolved</code> snippet</summary>
<br>

```json

{
  "pins" : [
    {
      "identity" : "abseil-cpp-swiftpm",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/abseil-cpp-SwiftPM.git",
      "state" : {
        "revision" : "583de9bd60f66b40e78d08599cc92036c2e7e4e1",
        "version" : "0.20220203.2"
      }
    },
    {
      "identity" : "boringssl-swiftpm",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/boringssl-SwiftPM.git",
      "state" : {
        "revision" : "dd3eda2b05a3f459fc3073695ad1b28659066eab",
        "version" : "0.9.1"
      }
    },
    {
      "identity" : "commonui_sdk_ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/zendesk/commonui_sdk_ios",
      "state" : {
        "revision" : "d6d40302c628bde17251c24553f18b5b47551b6b",
        "version" : "7.0.0"
      }
    },
    {
      "identity" : "core_sdk_ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/zendesk/core_sdk_ios",
      "state" : {
        "revision" : "c4c402fda96e3c21b47c7df34b0bd4e2d0489681",
        "version" : "3.0.0"
      }
    },
    {
      "identity" : "firebase-ios-sdk",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/firebase-ios-sdk",
      "state" : {
        "revision" : "f0926478fda955aef0dfbf99263b5c24b2ca5db4",
        "version" : "10.1.0"
      }
    },
    {
      "identity" : "googleappmeasurement",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleAppMeasurement.git",
      "state" : {
        "revision" : "71eb6700dd53a851473c48d392f00a3ab26699a6",
        "version" : "10.1.0"
      }
    },
    {
      "identity" : "googledatatransport",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleDataTransport.git",
      "state" : {
        "revision" : "5056b15c5acbb90cd214fe4d6138bdf5a740e5a8",
        "version" : "9.2.0"
      }
    },
    {
      "identity" : "googleutilities",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleUtilities.git",
      "state" : {
        "revision" : "68ea347bdb1a69e2d2ae2e25cd085b6ef92f64cb",
        "version" : "7.9.0"
      }
    },
    {
      "identity" : "grpc-ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/grpc/grpc-ios.git",
      "state" : {
        "revision" : "8440b914756e0d26d4f4d054a1c1581daedfc5b6",
        "version" : "1.44.3-grpc"
      }
    },
    {
      "identity" : "gtm-session-fetcher",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/gtm-session-fetcher.git",
      "state" : {
        "revision" : "d4289da23e978f37c344ea6a386e5546e2466294",
        "version" : "2.1.0"
      }
    },
    {
      "identity" : "kingfisher",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/onevcat/Kingfisher.git",
      "state" : {
        "revision" : "44e891bdb61426a95e31492a67c7c0dfad1f87c5",
        "version" : "7.4.1"
      }
    },
    {
      "identity" : "leveldb",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/leveldb.git",
      "state" : {
        "revision" : "0706abcc6b0bd9cedfbb015ba840e4a780b5159b",
        "version" : "1.22.2"
      }
    },
    {
      "identity" : "messaging_sdk_ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/zendesk/messaging_sdk_ios",
      "state" : {
        "revision" : "97678c795166b6bf8879ed51e3054ffaa033c883",
        "version" : "4.0.0"
      }
    },
    {
      "identity" : "messagingapi_sdk_ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/zendesk/messagingapi_sdk_ios",
      "state" : {
        "revision" : "503f60e2bfd8bca2b39eb515ef0ac3607bdc4d1d",
        "version" : "4.0.0"
      }
    },
    {
      "identity" : "nanopb",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/nanopb.git",
      "state" : {
        "revision" : "819d0a2173aff699fb8c364b6fb906f7cdb1a692",
        "version" : "2.30909.0"
      }
    },
    {
      "identity" : "nativemarkkit",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/andyfinnell/NativeMarkKit.git",
      "state" : {
        "revision" : "4833aa3f62ab3b846b2f8042418c71e5bebe167c",
        "version" : "2.1.1"
      }
    },
    {
      "identity" : "promises",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/promises.git",
      "state" : {
        "revision" : "3e4e743631e86c8c70dbc6efdc7beaa6e90fd3bb",
        "version" : "2.1.1"
      }
    },
    {
      "identity" : "purchases-ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/RevenueCat/purchases-ios.git",
      "state" : {
        "revision" : "f82a49e181a9ac775e8aebfac58859199bc8e7b7",
        "version" : "4.14.1"
      }
    },
    {
      "identity" : "sdkconfigurations_sdk_ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/zendesk/sdkconfigurations_sdk_ios",
      "state" : {
        "revision" : "a99da4df16e09b89ca6c4b576ca139a7d04efcf5",
        "version" : "2.0.0"
      }
    },
    {
      "identity" : "statefultabview",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/NicholasBellucci/StatefulTabView.git",
      "state" : {
        "revision" : "9faa432592874b6e20065f2aa63f20f72c5df71c",
        "version" : "0.1.10"
      }
    },
    {
      "identity" : "support_providers_sdk_ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/zendesk/support_providers_sdk_ios",
      "state" : {
        "revision" : "cdcf4704834a6daae4f61b4130cc369bbf10c7bf",
        "version" : "6.0.0"
      }
    },
    {
      "identity" : "support_sdk_ios",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/zendesk/support_sdk_ios",
      "state" : {
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        "version" : "6.0.0"
      }
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    {
      "identity" : "swift-log",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/apple/swift-log.git",
      "state" : {
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        "version" : "1.4.4"
      }
    },
    {
      "identity" : "swift-protobuf",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/apple/swift-protobuf.git",
      "state" : {
        "revision" : "88c7d15e1242fdb6ecbafbc7926426a19be1e98a",
        "version" : "1.20.2"
      }
    },
    {
      "identity" : "swiftui-introspect",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/siteline/SwiftUI-Introspect.git",
      "state" : {
        "branch" : "master",
        "revision" : "d3cbf32788250741d397cfb5bcd532c37aa1096d"
      }
    },
    {
      "identity" : "swiftuix",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/SwiftUIX/SwiftUIX",
      "state" : {
        "revision" : "1c2ba19b91a1541b803f9d1b01b360cae5a752fa",
        "version" : "0.1.3"
      }
    }
  ],
  "version" : 2
}


```

</details>


### If using CocoaPods, the project's Podfile.lock



<details>
<summary>Expand <code>Podfile.lock</code> snippet</summary>
<br>

```yml

Replace this line with the contents of your Podfile.lock!

```

</details>

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Uh oh!

Firebase Storage Global queue usage leads to thread explosion/threading issues #10487

Description

Reproducing the issue

Firebase SDK Version

Xcode Version

Installation Method

Firebase Product(s)

Targeted Platforms

Relevant Log Output

If using Swift Package Manager, the project's Package.resolved

If using CocoaPods, the project's Podfile.lock

Metadata

Assignees

Labels

Type

Fields

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Milestone

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Development

Uh oh!

Firebase Storage Global queue usage leads to thread explosion/threading issues #10487

Description

Description

Reproducing the issue

Firebase SDK Version

Xcode Version

Installation Method

Firebase Product(s)

Targeted Platforms

Relevant Log Output

If using Swift Package Manager, the project's Package.resolved

If using CocoaPods, the project's Podfile.lock

Metadata

Metadata

Assignees

Labels

Type

Fields

Projects

Milestone

Relationships

Development

Issue actions