code: public void setNFSUser(String user, String password) throws HostConfigFault, RuntimeFault, RemoteException {
          getVimService().setNFSUser(getMOR(), user, password);
      }
docs: Set NFS username and password on the host. The specified password is stored encrypted at the host and overwrites
  any previous password configuration. This information is only needed when the host has mounted NFS volumes with
  security types that require user credentials for accessing data. The password is used to acquire credentials that
  the NFS client needs to use in order to secure NFS traffic using RPCSECGSS. The client will access files on all
  volumes mounted on this host (that are mounted with the relevant security type) on behalf of specified user.
  <p>
  At present, this API supports only file system NFSv4.1.
  
  @param user     Username
  @param password Passowrd
  @throws HostConfigFault
  @throws RuntimeFault
  @throws RemoteException
  @since 6.0