Suppose that you could make use of only transient asynchronous communi-cation primitives, including only an asynchronous receive primitive. Howwould you implement primitives for transient synchronous communication?
Consider a synchronous send primitive. A simple implementation is to send amessage to the server using asynchronous communication, and subsequentlylet the caller continuously poll for an incoming acknowledgment or responsefrom the server. If we assume that the local operating system stores incom-ing messages into a local buer, then an alternative implementation is toblock the caller until it receives a signal from the operating system that amessage has arrived, after which the caller does an asynchronous receive.