Helper to make concurrent task group with any number of operations

Task+GroupOperations.swift

import _Concurrency

extension Task {

  // Create group with n tasks, executed concurrently. 
  // Returned array preserves original order of operations.
  static func withGroup<TaskResult>(operations: [() async throws -> TaskResult]) async throws -> [TaskResult] {
    return try await Task.withGroup(resultType: (Int, TaskResult).self) { group in
      for (idx, provider) in operations.enumerated() {
        await group.add {
          (idx, try await provider())
        }
      }

      var results: [TaskResult?] = operations.map { _ in nil }
      while let (idx, result) = try await group.next() {
        results[idx] = result
      }
      return results.compactMap { $0 }
    }
  }
}