code: public ServiceFuture<Void> deleteUserAsync(String poolId, String nodeId, String userName, final ServiceCallback<Void> serviceCallback) {
          return ServiceFuture.fromHeaderResponse(deleteUserWithServiceResponseAsync(poolId, nodeId, userName), serviceCallback);
      }
docs: Deletes a user account from the specified compute node.
  You can delete a user account to a node only when it is in the idle or running state.
  
  @param poolId The ID of the pool that contains the compute node.
  @param nodeId The ID of the machine on which you want to delete a user account.
  @param userName The name of the user account to delete.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object