/// <summary>
 /// Create user defined role.
 /// </summary>
 /// <param name="policy">admin configuration parameters, pass in null for defaults</param>
 /// <param name="roleName">role name</param>
 /// <param name="privileges">privileges assigned to the role.</param>
 /// <exception cref="AerospikeException">if command fails </exception>
 public void CreateRole(AdminPolicy policy, string roleName, IList<Privilege> privileges)
 {
     AdminCommand command = new AdminCommand();
     command.CreateRole(cluster, policy, roleName, privileges);
 }