When you call for a HTTP request, unless until it finished the processing of assigned task, the Synchronous HTTP handler doesn't return any value. It will return a value after successful execution of sent request.
But in case of asynchronous handler, it will run a process independently and it will send a response to the end user. When you are working with some lengthy application processes, then it is advisable to use Asynchronous handler. Here the user doesn't need to wait until it finishes before receiving a response from the server.
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