/// <summary>
/// Enqueue a callback as a work item to be invoked with a provided <see cref="TaskEnv"/>.
/// </summary>
/// <typeparam name="T">Result value type of callback.</typeparam>
/// <param name="dispatchQueue">DispatchQueue to enqueue work into.</param>
/// <param name="callback">Work item callback.</param>
/// <param name="env">Environment for work item invocation.</param>
/// <param name="result">Synchronization handle for work item.</param>
/// <returns>The synchronization handle provided to the method.</returns>
public static Result <T> QueueWorkItemWithEnv <T>(this IDispatchQueue dispatchQueue, Func <T> callback, TaskEnv env, Result <T> result)
{
if (env == null)
{
throw new ArgumentException("env");
}
dispatchQueue.QueueWorkItem(env.MakeAction(callback, result));
return(result);
}