ef="../../../../javax/ws/rs/core/Response.Status.html#SERVICE_UNAVAILABLE"><code>HTTP 503 (Service unavailable)</code></a>
 error response.
 </p>
 <p>
 Invoking a <code>cancel(...)</code> method multiple times to cancel request processing has the same
 effect as canceling the request processing only once. Invoking a <code>cancel(...)</code> method on
 an asynchronous response instance that has already been cancelled or resumed has no effect and the
 method call is ignored while returning <code>true</code>, 