@Override
            public AssociateHealthCheckResult call() throws Exception {
                AssociateHealthCheckResult result = null;

                try {
                    result = executeAssociateHealthCheck(finalRequest);
                } catch (Exception ex) {
                    if (asyncHandler != null) {
                        asyncHandler.onError(ex);
                    }
                    throw ex;
                }

                if (asyncHandler != null) {
                    asyncHandler.onSuccess(finalRequest, result);
                }
                return result;
            }
Returns the executor service used by this client to execute async requests.

@return The executor service used by this client to execute async requests.
aws-java-sdk-shield/src/main/java/com/amazonaws/services/shield/AWSShieldAsyncClient.java