BatchGet

//====================================================================//
public void LoadPlayers(List<string> facebookIDs, System.Action<List<PlayerDatabaseItem>> callback)
{
    StartCoroutine(LoadPlayersAsync(facebookIDs, callback));
}
//====================================================================//
// https://forums.aws.amazon.com/thread.jspa?threadID=240744
// http://gamedev.stackexchange.com/questions/50864/mixing-threads-and-coroutines-in-unity3d-mobile
private IEnumerator LoadPlayersAsync(List<string> facebookIDs, System.Action<List<PlayerDatabaseItem>> callback)
{
    bool isDone = false;
    BatchGet<PlayerDatabaseItem> batchGet = null;
    Thread thread = new Thread(() =>
    {
        // This is a synchronous call that creates another thread and waits.
        // We must wait for it too inside this thread and handle the
        // response within the coroutine (main thread).
        batchGet = m_dynamoDBContext.CreateBatchGet<PlayerDatabaseItem>();

        isDone = true;
    });
    thread.Start();

    while (isDone == false)
    {
        yield return null;
    }

    foreach (string facebookID in facebookIDs)
    {
        batchGet.AddKey(facebookID);
    }

    batchGet.ExecuteAsync((AmazonDynamoDBResult responseObject) =>
    {
        if (responseObject.Exception != null)
        {
            Debug.Log("F84AWSManager.LoadPlayers - Failure: " + responseObject.Exception.Message);
        }
        else
        {
            if (callback != null) callback(batchGet.Results);
        }
    });
}
//====================================================================//