We are using basically two CompletableFuture methods:
- supplyAsync: This will start an async call to whatever you put inside of it. We put in a lambda call.
- thenAcceptAsync: Once the async process is done, the returning value will come here. Thanks to lambdas, we can call this returning value as u (and could be whatever we want). Then, we use it to write it down to the asynchronous response.
