code: public ServiceFuture<ExpressRouteCircuitAuthorizationInner> getAsync(String resourceGroupName, String circuitName, String authorizationName, final ServiceCallback<ExpressRouteCircuitAuthorizationInner> serviceCallback) {
          return ServiceFuture.fromResponse(getWithServiceResponseAsync(resourceGroupName, circuitName, authorizationName), serviceCallback);
      }
docs: Gets the specified authorization from the specified express route circuit.
  
  @param resourceGroupName The name of the resource group.
  @param circuitName The name of the express route circuit.
  @param authorizationName The name of the authorization.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object