code: public ServiceFuture<List<VirtualNetworkGatewayConnectionListEntityInner>> listConnectionsAsync(final String resourceGroupName, final String virtualNetworkGatewayName, final ListOperationCallback<VirtualNetworkGatewayConnectionListEntityInner> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              listConnectionsSinglePageAsync(resourceGroupName, virtualNetworkGatewayName),
              new Func1<String, Observable<ServiceResponse<Page<VirtualNetworkGatewayConnectionListEntityInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<VirtualNetworkGatewayConnectionListEntityInner>>> call(String nextPageLink) {
                      return listConnectionsNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: Gets all the connections in a virtual network gateway.
  
  @param resourceGroupName The name of the resource group.
  @param virtualNetworkGatewayName The name of the virtual network gateway.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object