Throttling. A problem with remote procedure calls (RPCs) is that too many of them on a single receiver at the same time can overload the receiver. This can cause performance degradation and even cause the receiver to crash. Because the messaging system queues up requests until the receiver is ready to process them, the receiver can control the rate at which it consumes requests so as not to become overloaded by too many simultaneous requests. The callers are unaffected by this throttling because the communication is asynchronous, so the callers are not blocked waiting on the receiver.
