code: public VnetGatewayInner updateVnetGateway(String resourceGroupName, String name, String vnetName, String gatewayName, VnetGatewayInner connectionEnvelope) {
          return updateVnetGatewayWithServiceResponseAsync(resourceGroupName, name, vnetName, gatewayName, connectionEnvelope).toBlocking().single().body();
      }
docs: Update a Virtual Network gateway.
  Update a Virtual Network gateway.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param name Name of the App Service plan.
  @param vnetName Name of the Virtual Network.
  @param gatewayName Name of the gateway. Only the 'primary' gateway is supported.
  @param connectionEnvelope Definition of the gateway.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the VnetGatewayInner object if successful.