/// <summary>
 /// Retrieve all roles.
 /// </summary>
 /// <param name="policy">admin configuration parameters, pass in null for defaults</param>
 /// <exception cref="AerospikeException">if command fails</exception>
 public List<Role> QueryRoles(AdminPolicy policy)
 {
     AdminCommand.RoleCommand command = new AdminCommand.RoleCommand(100);
     return command.QueryRoles(cluster, policy);
 }
 /// <summary>
 /// Retrieve role definition.
 /// </summary>
 /// <param name="policy">admin configuration parameters, pass in null for defaults</param>
 /// <param name="roleName">role name filter</param>
 /// <exception cref="AerospikeException">if command fails</exception>
 public Role QueryRole(AdminPolicy policy, string roleName)
 {
     AdminCommand.RoleCommand command = new AdminCommand.RoleCommand(1);
     return command.QueryRole(cluster, policy, roleName);
 }