code: public ServiceFuture<VirtualMachineExtensionsListResultInner> getExtensionsAsync(String resourceGroupName, String vmName, String expand, final ServiceCallback<VirtualMachineExtensionsListResultInner> serviceCallback) {
          return ServiceFuture.fromResponse(getExtensionsWithServiceResponseAsync(resourceGroupName, vmName, expand), serviceCallback);
      }
docs: The operation to get all extensions of a Virtual Machine.
  
  @param resourceGroupName The name of the resource group.
  @param vmName The name of the virtual machine containing the extension.
  @param expand The expand expression to apply on the operation.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object