Delegate Command with Async Function in Xamarin forms

In Xamarin forms we have delegate commands like this:

        /// Gets or sets the logout command.
        /// </summary>
        /// <value>
        /// The logout command.
        /// </value>
        public DelegateCommand LogoutCommand { get; set; }

Which is initialized in the constructor like this:

this.LogoutCommand = new DelegateCommand(this.ExecuteLogoutCommand);

Currently, the ExecuteLogoutCommand is return void type, but I wish to make it Task as it has an async task. But doing so breaks the initialization in the constructor. Any help here?

Update The following link helped me: https://johnthiriet.com/mvvm-going-async-with-async-command/

But now I get this error in my Unit Tests:

MobileApp.Core.UnitTests.Add.ConfirmationPageViewModelUnitTests.OnNavigatedToBackBehavior threw exception: System.MissingMethodException: Method not found: 'MobileApp.Core.IServices.IAsyncDelegateCommand MobileApp.Core.ViewModel.Add.ConfirmationPageViewModel.get_GoBackHomeCommand()'