title: boost asio service queue deepness and policies
body: <p>I understand a running asio service is like a queue I can use to post tasks a thread will execute sequentially. However, as any queue, I guess there are limits. Is it possible to set this limit for asio services? Is it possible to set what policy to follow when the queue is full (i.e. blocking, non blocking, etc.)?</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>Suppose I have a thread running an asio::service and a timer posting each 10ms a task to this thread. The task reception is bound to a method invokation which will make the thread sleeping for 100ms. I have therefore a timer posting 100 tasks a second to a thread which is capable of performing 10 tasks each second. It is evident that this situation will diverge. However, when dealing with queues, there are usually means to dimension the queue deepness (100? 1000? posts enqueued, etc.) or to specify the policy a sender should follow when the queue is full (i.e. shall it wait or shall it drop the request and continue?). My question is Ho to set these features in asio::service?</p>