Implementation: An eight-bit (Sixteen ... "according to the number of requests, depending on the number of requests) is used to represent the request, and each bit of the number represents a corresponding request. This bit indicates a request, 0 means no request. Finally, this number is used as a request parameter. We call this figure as the request level. Advantages: 1. When the request is a lot, you do not need to specify a parameter as a request for the traditional parameter request, simply specify the corresponding bit; 2. Reduce the amount of information transfer; 3. Receive the requestor can be tested Request level of each bit to get request information.
