* <li>Implementations <b>SHOULD NOT</b> perform CPU-intensive operations on the calling thread.
* <li>Implementations <b>MUST NOT block the calling thread</b> - to do so could lead to deadlock
* <li>Implementations <b>SHOULD NOT</b> perform CPU-intensive operations on the calling thread.
* <li>Implementations <b>MUST NOT block the calling thread</b> - to do so could lead to deadlock