SSL implements asynchronous capabilities through an <b>ASYNC_JOB</b>. This represents code that can be started and executes until some event occurs. At that point the code can be paused and control returns to user code until some subsequent event indicates that the job can be resumed. It&#39;s OpenSSL specific implementation of cooperative multitasking.</p>

<p>The creation of an <b>ASYNC_JOB</b> is a relatively expensive operation. Therefore, for efficiency reasons, jobs can be created up front and reused 