public static Member <object> GetCurrentAwaiter(this IAsyncStateMachine sm)
{
var candidateAwaiters = new List <Member <object> >();
var fieldInfos = sm.GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Instance);
foreach (var fieldInfo in fieldInfos)
{
if (!fieldInfo.Name.StartsWith("<>u__"))
{
continue;
}
var awaiter = fieldInfo.GetValue(sm); if (awaiter == null)
{
continue;
}
// typical awaiters have a field named "m_task" of type Task
var taskFieldInfo = awaiter.GetType().GetField("m_task", BindingFlags.NonPublic | BindingFlags.Instance);
if (taskFieldInfo != null && typeof(Task).IsAssignableFrom(taskFieldInfo.FieldType))
{
var m_task = taskFieldInfo.GetValue(awaiter);
if (m_task == null)
{
continue;
}
}
candidateAwaiters.Add(CreateMember(fieldInfo.Name, awaiter));
}
if (candidateAwaiters.Count != 1)
{
throw new NotSupportedException($"Async method {sm.Name()} has awaiters that are too complicated to process");
}
return(candidateAwaiters[0]);
}
