Windows Azure Queue messages have a delay, in seconds, that you specify when inserting a message onto the queue. A message won't be visible until that timeout delay is hit. See this MSDN article to see the API details.
The invisibility timeout is implemented in the various language SDK implementations as well. Since you're working with C#, here's what the AddMessage()
call would look like. Note the 3rd parameter of AddMessage()
specifies the invisibility timeout:
var acct = CloudStorageAccount.DevelopmentStorageAccount;
var queueClient = acct.CreateCloudQueueClient();
var queue = queueClient.GetQueueReference("myqueue");
queue.CreateIfNotExist();
var msg = new CloudQueueMessage("test message");
queue.AddMessage(msg, TimeSpan.FromHours(2), TimeSpan.FromMinutes(30));