Erro ao compilar AsyncStack<> com Swift 6

Estou migrando para o Swift 6 e recebo um erro enquanto o Swift 5 compila.

O envio de 'newElement' corre o risco de causar disputas de dados

Por que isso acontece e como posso corrigir?

actor AsyncStack<Element> {
  private var storage = [Element]()
  private var awaiters = [CheckedContinuation<Element,Error>]()
  
  
  /// Push a new element onto the stack
  /// - Parameter newElement: The element to push
  /// - Returns: Void
  
  public func push(_ newElement: Element) async -> Void {
    if !awaiters.isEmpty {
      let awaiter = awaiters.removeFirst()
      awaiter.resume(returning: newElement) // ERROR in this line
    } else {
      storage.insert(newElement, at: 0)
    }
  }
  
  /// Pop the  element at the top of the stack or wait until an element becomes available
  /// - Returns: The popped element
  
  public func popOrWait() async throws -> Element {
    if let element = storage.popLast() {
      return element
    }
    return try await withCheckedThrowingContinuation { continuation in
      awaiters.append(continuation)
    }
  }
}