code: public ServiceFuture<FileServerInner> getByResourceGroupAsync(String resourceGroupName, String fileServerName, final ServiceCallback<FileServerInner> serviceCallback) {
          return ServiceFuture.fromResponse(getByResourceGroupWithServiceResponseAsync(resourceGroupName, fileServerName), serviceCallback);
      }
docs: Gets information about the specified Cluster.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param fileServerName The name of the file server within the specified resource group. File server names can only contain a combination of alphanumeric characters along with dash (-) and underscore (_). The name must be from 1 through 64 characters long.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object